The vaccine deployment in December 2020 signaled a turning point in the COVID-19 pandemic. By the end of May 2021, 40% of the U.S. population was fully vaccinated. But as vaccination rates lagged over the summer, new surges of COVID-19 came, including Delta in the summer of 2021, and now the Omicron variant, which comprises the majority of cases in the U.S.

Researchers around the world have reported that Omicron is more transmissible than Delta, making breakthrough and repeat infections more likely. Early research suggests this strain may cause less severe illness than Delta and the original virus, however, health officials have warned an Omicron-driven surge could still increase hospitalization and death rates—especially in areas with less vaccinated populations.

The United States as of Jan. 18 reached 852,339 COVID-19-related deaths and 66.7 million COVID-19 cases, according to Johns Hopkins University. Currently, 62.9% of the population is fully vaccinated, and 38.1% have received booster doses.

Stacker compiled a list of the counties with highest COVID-19 infection rates in California using data from the U.S. Department of Health & Human Services and vaccination data from Covid Act Now. Counties are ranked by the highest infection rate per 100,000 residents within the week leading up to Jan. 14, 2021. Cumulative cases per 100,000 served as a tiebreaker.

Keep reading to see whether your county ranks among the highest COVID-19 infection rates in your state.

#50. Siskiyou County, CA

– New cases per 100k in the past week: 710 (309 new cases, +247% change from previous week)
– Cumulative cases per 100k: 12,258 (5,337 total cases)
— 27.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 142 (62 total deaths)
— 26.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 46.7% (20,323 fully vaccinated)
— 30.6% lower vaccination rate than California

#49. Glenn County, CA

– New cases per 100k in the past week: 726 (206 new cases, +102% change from previous week)
– Cumulative cases per 100k: 17,726 (5,033 total cases)
— 5.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 137 (39 total deaths)
— 29.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 52.7% (14,961 fully vaccinated)
— 21.7% lower vaccination rate than California

#48. Plumas County, CA

– New cases per 100k in the past week: 760 (143 new cases, +309% change from previous week)
– Cumulative cases per 100k: 11,868 (2,232 total cases)
— 29.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 64 (12 total deaths)
— 67.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 53.6% (10,080 fully vaccinated)
— 20.4% lower vaccination rate than California

#47. Lake County, CA

– New cases per 100k in the past week: 795 (512 new cases, +365% change from previous week)
– Cumulative cases per 100k: 12,209 (7,861 total cases)
— 27.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 182 (117 total deaths)
— 6.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 52.6% (33,844 fully vaccinated)
— 21.8% lower vaccination rate than California

#46. Butte County, CA

– New cases per 100k in the past week: 867 (1,901 new cases, +115% change from previous week)
– Cumulative cases per 100k: 13,409 (29,391 total cases)
— 20.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 159 (348 total deaths)
— 18.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 51.1% (111,918 fully vaccinated)
— 24.1% lower vaccination rate than California

#45. Calaveras County, CA

– New cases per 100k in the past week: 919 (422 new cases, +249% change from previous week)
– Cumulative cases per 100k: 11,504 (5,281 total cases)
— 31.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 203 (93 total deaths)
— 4.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 51.6% (23,679 fully vaccinated)
— 23.3% lower vaccination rate than California

#44. Amador County, CA

– New cases per 100k in the past week: 921 (366 new cases, +193% change from previous week)
– Cumulative cases per 100k: 16,309 (6,483 total cases)
— 3.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 179 (71 total deaths)
— 7.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 50.7% (20,173 fully vaccinated)
— 24.7% lower vaccination rate than California

#43. Tehama County, CA

– New cases per 100k in the past week: 968 (630 new cases, +367% change from previous week)
– Cumulative cases per 100k: 17,385 (11,315 total cases)
— 3.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 217 (141 total deaths)
— 11.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 41.0% (26,682 fully vaccinated)
— 39.1% lower vaccination rate than California

#42. Mariposa County, CA

– New cases per 100k in the past week: 988 (170 new cases, +188% change from previous week)
– Cumulative cases per 100k: 10,423 (1,793 total cases)
— 38.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 35 (6 total deaths)
— 82.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 43.0% (7,405 fully vaccinated)
— 36.1% lower vaccination rate than California

#41. El Dorado County, CA

– New cases per 100k in the past week: 1,008 (1,943 new cases, +126% change from previous week)
– Cumulative cases per 100k: 11,594 (22,358 total cases)
— 31.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 91 (175 total deaths)
— 53.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 59.0% (113,767 fully vaccinated)
— 12.3% lower vaccination rate than California

#40. Nevada County, CA

– New cases per 100k in the past week: 1,059 (1,056 new cases, +191% change from previous week)
– Cumulative cases per 100k: 12,119 (12,089 total cases)
— 28.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 111 (111 total deaths)
— 42.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 61.3% (61,151 fully vaccinated)
— 8.9% lower vaccination rate than California

#39. Stanislaus County, CA

– New cases per 100k in the past week: 1,116 (6,144 new cases, +204% change from previous week)
– Cumulative cases per 100k: 18,596 (102,402 total cases)
— 10.2% more cases per 100k residents than California
– Cumulative deaths per 100k: 249 (1,373 total deaths)
— 28.4% more deaths per 100k residents than California
– Population that is fully vaccinated: 53.9% (296,859 fully vaccinated)
— 19.9% lower vaccination rate than California

#38. Humboldt County, CA

– New cases per 100k in the past week: 1,152 (1,562 new cases, +122% change from previous week)
– Cumulative cases per 100k: 9,932 (13,463 total cases)
— 41.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 90 (122 total deaths)
— 53.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 63.7% (86,319 fully vaccinated)
— 5.3% lower vaccination rate than California

#37. Mendocino County, CA

– New cases per 100k in the past week: 1,177 (1,021 new cases, +271% change from previous week)
– Cumulative cases per 100k: 12,008 (10,417 total cases)
— 28.9% less cases per 100k residents than California
– Cumulative deaths per 100k: 119 (103 total deaths)
— 38.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.0% (57,245 fully vaccinated)
— 1.9% lower vaccination rate than California

#36. Sutter County, CA

– New cases per 100k in the past week: 1,184 (1,148 new cases, +181% change from previous week)
– Cumulative cases per 100k: 17,255 (16,732 total cases)
— 2.2% more cases per 100k residents than California
– Cumulative deaths per 100k: 203 (197 total deaths)
— 4.6% more deaths per 100k residents than California
– Population that is fully vaccinated: 57.0% (55,320 fully vaccinated)
— 15.3% lower vaccination rate than California

#35. Tulare County, CA

– New cases per 100k in the past week: 1,184 (5,519 new cases, +249% change from previous week)
– Cumulative cases per 100k: 20,761 (96,787 total cases)
— 23.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 256 (1,192 total deaths)
— 32.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 50.9% (237,259 fully vaccinated)
— 24.4% lower vaccination rate than California

#34. Madera County, CA

– New cases per 100k in the past week: 1,221 (1,921 new cases, +265% change from previous week)
– Cumulative cases per 100k: 18,938 (29,794 total cases)
— 12.2% more cases per 100k residents than California
– Cumulative deaths per 100k: 209 (329 total deaths)
— 7.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 51.1% (80,369 fully vaccinated)
— 24.1% lower vaccination rate than California

#33. Marin County, CA

– New cases per 100k in the past week: 1,236 (3,198 new cases, +98% change from previous week)
– Cumulative cases per 100k: 10,056 (26,028 total cases)
— 40.4% less cases per 100k residents than California
– Cumulative deaths per 100k: 97 (251 total deaths)
— 50.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 85.3% (220,702 fully vaccinated)
— 26.7% higher vaccination rate than California

#32. Merced County, CA

– New cases per 100k in the past week: 1,246 (3,459 new cases, +227% change from previous week)
– Cumulative cases per 100k: 18,525 (51,440 total cases)
— 9.7% more cases per 100k residents than California
– Cumulative deaths per 100k: 256 (710 total deaths)
— 32.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 48.1% (133,697 fully vaccinated)
— 28.5% lower vaccination rate than California

#31. Tuolumne County, CA

– New cases per 100k in the past week: 1,250 (681 new cases, +240% change from previous week)
– Cumulative cases per 100k: 16,598 (9,042 total cases)
— 1.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 167 (91 total deaths)
— 13.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 50.5% (27,521 fully vaccinated)
— 25.0% lower vaccination rate than California

#30. Monterey County, CA

– New cases per 100k in the past week: 1,252 (5,434 new cases, +176% change from previous week)
– Cumulative cases per 100k: 14,413 (62,561 total cases)
— 14.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 149 (647 total deaths)
— 23.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 68.6% (297,955 fully vaccinated)
— 1.9% higher vaccination rate than California

#29. Yuba County, CA

– New cases per 100k in the past week: 1,255 (987 new cases, +192% change from previous week)
– Cumulative cases per 100k: 16,015 (12,599 total cases)
— 5.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 128 (101 total deaths)
— 34.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 46.1% (36,277 fully vaccinated)
— 31.5% lower vaccination rate than California

#28. Placer County, CA

– New cases per 100k in the past week: 1,278 (5,089 new cases, +179% change from previous week)
– Cumulative cases per 100k: 13,054 (51,997 total cases)
— 22.7% less cases per 100k residents than California
– Cumulative deaths per 100k: 126 (501 total deaths)
— 35.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 64.2% (255,790 fully vaccinated)
— 4.6% lower vaccination rate than California

#27. Fresno County, CA

– New cases per 100k in the past week: 1,293 (12,914 new cases, +254% change from previous week)
– Cumulative cases per 100k: 17,979 (179,628 total cases)
— 6.5% more cases per 100k residents than California
– Cumulative deaths per 100k: 242 (2,413 total deaths)
— 24.7% more deaths per 100k residents than California
– Population that is fully vaccinated: 57.8% (577,238 fully vaccinated)
— 14.1% lower vaccination rate than California

#26. Kern County, CA

– New cases per 100k in the past week: 1,306 (11,760 new cases, +364% change from previous week)
– Cumulative cases per 100k: 19,567 (176,142 total cases)
— 15.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 215 (1,933 total deaths)
— 10.8% more deaths per 100k residents than California
– Population that is fully vaccinated: 50.4% (453,851 fully vaccinated)
— 25.1% lower vaccination rate than California

#25. Kings County, CA

– New cases per 100k in the past week: 1,321 (2,021 new cases, +211% change from previous week)
– Cumulative cases per 100k: 25,651 (39,230 total cases)
— 52.0% more cases per 100k residents than California
– Cumulative deaths per 100k: 256 (391 total deaths)
— 32.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 42.3% (64,642 fully vaccinated)
— 37.1% lower vaccination rate than California

#24. Solano County, CA

– New cases per 100k in the past week: 1,394 (6,238 new cases, +122% change from previous week)
– Cumulative cases per 100k: 13,282 (59,454 total cases)
— 21.3% less cases per 100k residents than California
– Cumulative deaths per 100k: 87 (388 total deaths)
— 55.2% less deaths per 100k residents than California
– Population that is fully vaccinated: 63.5% (284,403 fully vaccinated)
— 5.6% lower vaccination rate than California

#23. Napa County, CA

– New cases per 100k in the past week: 1,406 (1,937 new cases, +75% change from previous week)
– Cumulative cases per 100k: 12,810 (17,645 total cases)
— 24.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 79 (109 total deaths)
— 59.3% less deaths per 100k residents than California
– Population that is fully vaccinated: 75.4% (103,875 fully vaccinated)
— 12.0% higher vaccination rate than California

#22. San Luis Obispo County, CA

– New cases per 100k in the past week: 1,471 (4,165 new cases, +118% change from previous week)
– Cumulative cases per 100k: 14,104 (39,929 total cases)
— 16.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 132 (373 total deaths)
— 32.0% less deaths per 100k residents than California
– Population that is fully vaccinated: 62.1% (175,812 fully vaccinated)
— 7.7% lower vaccination rate than California

#21. Sonoma County, CA

– New cases per 100k in the past week: 1,520 (7,513 new cases, +136% change from previous week)
– Cumulative cases per 100k: 11,608 (57,381 total cases)
— 31.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 84 (417 total deaths)
— 56.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 75.5% (373,043 fully vaccinated)
— 12.2% higher vaccination rate than California

#20. Santa Cruz County, CA

– New cases per 100k in the past week: 1,541 (4,211 new cases, +175% change from previous week)
– Cumulative cases per 100k: 10,944 (29,900 total cases)
— 35.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 86 (235 total deaths)
— 55.7% less deaths per 100k residents than California
– Population that is fully vaccinated: 72.4% (197,720 fully vaccinated)
— 7.6% higher vaccination rate than California

#19. San Benito County, CA

– New cases per 100k in the past week: 1,541 (968 new cases, +75% change from previous week)
– Cumulative cases per 100k: 15,995 (10,046 total cases)
— 5.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 140 (88 total deaths)
— 27.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.8% (42,581 fully vaccinated)
— 0.7% higher vaccination rate than California

#18. Contra Costa County, CA

– New cases per 100k in the past week: 1,689 (19,486 new cases, +140% change from previous week)
– Cumulative cases per 100k: 12,129 (139,908 total cases)
— 28.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 93 (1,077 total deaths)
— 52.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 79.4% (915,326 fully vaccinated)
— 18.0% higher vaccination rate than California

#17. San Joaquin County, CA

– New cases per 100k in the past week: 1,694 (12,911 new cases, +206% change from previous week)
– Cumulative cases per 100k: 17,040 (129,868 total cases)
— 0.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 256 (1,948 total deaths)
— 32.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 57.6% (438,791 fully vaccinated)
— 14.4% lower vaccination rate than California

#16. Yolo County, CA

– New cases per 100k in the past week: 1,719 (3,790 new cases, +105% change from previous week)
– Cumulative cases per 100k: 13,078 (28,837 total cases)
— 22.5% less cases per 100k residents than California
– Cumulative deaths per 100k: 122 (270 total deaths)
— 37.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 67.0% (147,777 fully vaccinated)
— 0.4% lower vaccination rate than California

#15. Sacramento County, CA

– New cases per 100k in the past week: 1,758 (27,283 new cases, +199% change from previous week)
– Cumulative cases per 100k: 13,917 (216,001 total cases)
— 17.6% less cases per 100k residents than California
– Cumulative deaths per 100k: 160 (2,489 total deaths)
— 17.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 64.0% (994,000 fully vaccinated)
— 4.9% lower vaccination rate than California

#14. Riverside County, CA

– New cases per 100k in the past week: 1,804 (44,577 new cases, +138% change from previous week)
– Cumulative cases per 100k: 19,361 (478,326 total cases)
— 14.7% more cases per 100k residents than California
– Cumulative deaths per 100k: 225 (5,565 total deaths)
— 16.0% more deaths per 100k residents than California
– Population that is fully vaccinated: 55.9% (1,381,795 fully vaccinated)
— 16.9% lower vaccination rate than California

#13. Alameda County, CA

– New cases per 100k in the past week: 1,839 (30,731 new cases, +146% change from previous week)
– Cumulative cases per 100k: 10,790 (180,332 total cases)
— 36.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 94 (1,563 total deaths)
— 51.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 78.4% (1,310,548 fully vaccinated)
— 16.5% higher vaccination rate than California

#12. Santa Barbara County, CA

– New cases per 100k in the past week: 1,843 (8,231 new cases, +126% change from previous week)
– Cumulative cases per 100k: 14,170 (63,270 total cases)
— 16.1% less cases per 100k residents than California
– Cumulative deaths per 100k: 129 (578 total deaths)
— 33.5% less deaths per 100k residents than California
– Population that is fully vaccinated: 66.2% (295,647 fully vaccinated)
— 1.6% lower vaccination rate than California

#11. San Francisco County, CA

– New cases per 100k in the past week: 1,891 (16,674 new cases, +109% change from previous week)
– Cumulative cases per 100k: 10,501 (92,568 total cases)
— 37.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 78 (691 total deaths)
— 59.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 81.5% (718,307 fully vaccinated)
— 21.1% higher vaccination rate than California

#10. San Mateo County, CA

– New cases per 100k in the past week: 1,906 (14,608 new cases, +95% change from previous week)
– Cumulative cases per 100k: 11,111 (85,171 total cases)
— 34.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 76 (582 total deaths)
— 60.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 81.4% (623,984 fully vaccinated)
— 21.0% higher vaccination rate than California

#9. Santa Clara County, CA

– New cases per 100k in the past week: 1,933 (37,261 new cases, +153% change from previous week)
– Cumulative cases per 100k: 11,337 (218,569 total cases)
— 32.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 102 (1,971 total deaths)
— 47.4% less deaths per 100k residents than California
– Population that is fully vaccinated: 82.8% (1,596,501 fully vaccinated)
— 23.0% higher vaccination rate than California

#8. Orange County, CA

– New cases per 100k in the past week: 1,997 (63,411 new cases, +114% change from previous week)
– Cumulative cases per 100k: 14,221 (451,612 total cases)
— 15.8% less cases per 100k residents than California
– Cumulative deaths per 100k: 186 (5,912 total deaths)
— 4.1% less deaths per 100k residents than California
– Population that is fully vaccinated: 69.9% (2,218,930 fully vaccinated)
— 3.9% higher vaccination rate than California

#7. San Bernardino County, CA

– New cases per 100k in the past week: 2,043 (44,538 new cases, +126% change from previous week)
– Cumulative cases per 100k: 21,249 (463,256 total cases)
— 25.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 285 (6,222 total deaths)
— 46.9% more deaths per 100k residents than California
– Population that is fully vaccinated: 53.9% (1,175,096 fully vaccinated)
— 19.9% lower vaccination rate than California

#6. Ventura County, CA

– New cases per 100k in the past week: 2,155 (18,233 new cases, +157% change from previous week)
– Cumulative cases per 100k: 16,336 (138,203 total cases)
— 3.2% less cases per 100k residents than California
– Cumulative deaths per 100k: 144 (1,220 total deaths)
— 25.8% less deaths per 100k residents than California
– Population that is fully vaccinated: 69.1% (584,461 fully vaccinated)
— 2.7% higher vaccination rate than California

#5. Mono County, CA

– New cases per 100k in the past week: 2,202 (318 new cases, +184% change from previous week)
– Cumulative cases per 100k: 17,668 (2,552 total cases)
— 4.7% more cases per 100k residents than California
– Cumulative deaths per 100k: 28 (4 total deaths)
— 85.6% less deaths per 100k residents than California
– Population that is fully vaccinated: 61.7% (8,919 fully vaccinated)
— 8.3% lower vaccination rate than California

#4. Imperial County, CA

– New cases per 100k in the past week: 2,292 (4,153 new cases, +200% change from previous week)
– Cumulative cases per 100k: 26,274 (47,613 total cases)
— 55.6% more cases per 100k residents than California
– Cumulative deaths per 100k: 449 (814 total deaths)
— 131.4% more deaths per 100k residents than California
– Population that is fully vaccinated: 82.7% (149,796 fully vaccinated)
— 22.9% higher vaccination rate than California

#3. Inyo County, CA

– New cases per 100k in the past week: 2,295 (414 new cases, +82% change from previous week)
– Cumulative cases per 100k: 18,887 (3,407 total cases)
— 11.9% more cases per 100k residents than California
– Cumulative deaths per 100k: 272 (49 total deaths)
— 40.2% more deaths per 100k residents than California
– Population that is fully vaccinated: 59.6% (10,748 fully vaccinated)
— 11.4% lower vaccination rate than California

#2. San Diego County, CA

– New cases per 100k in the past week: 2,845 (94,991 new cases, +128% change from previous week)
– Cumulative cases per 100k: 17,605 (587,704 total cases)
— 4.3% more cases per 100k residents than California
– Cumulative deaths per 100k: 136 (4,529 total deaths)
— 29.9% less deaths per 100k residents than California
– Population that is fully vaccinated: 77.8% (2,597,723 fully vaccinated)
— 15.6% higher vaccination rate than California

#1. Los Angeles County, CA

– New cases per 100k in the past week: 2,850 (286,133 new cases, +102% change from previous week)
– Cumulative cases per 100k: 20,814 (2,089,532 total cases)
— 23.3% more cases per 100k residents than California
– Cumulative deaths per 100k: 275 (27,601 total deaths)
— 41.8% more deaths per 100k residents than California
– Population that is fully vaccinated: 70.0% (7,026,080 fully vaccinated)
— 4.0% higher vaccination rate than California

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