After adding over 1,076,000 new cases throughout the last week, the U.S. now has more than 41.2 million confirmed cases of COVID-19. There have been more than 650,000 COVID-19-related deaths — the highest death toll of any country.

New cases continue to rise at a steady rate. In the past week, there were an average of 49.5 daily new coronavirus cases per 100,000 Americans — essentially unchanged from the week prior, when there were an average of 45.4 daily new coronavirus cases per 100,000 people.

While COVID-19 has spread to nearly every part of the country, cities continue to be the sites of major outbreaks. Experts agree that the virus is more likely to spread in group settings where large numbers of people routinely have close contact with one another, such as colleges, nursing homes, bars, and restaurants. Metropolitan areas with a high degree of connectivity between neighborhoods and a large population may be particularly at-risk.

The Sacramento-Roseville-Folsom, CA, metro area consists of Sacramento County, Placer County, Yolo County, and one other county. In the past week, there were an average of 37.1 new coronavirus cases every day per 100,000 Sacramento residents, less than the national figure. The metro area’s average daily case growth in the most recent week is a decrease from the week prior, when there was an average of 63.4 daily new cases per 100,000 Sacramento residents.

The spread of coronavirus depends on a variety of factors and can vary even between neighboring counties. Within the Sacramento-Roseville-Folsom metro area, COVID-19 is growing the fastest in Placer County. There were an average of 41.9 new cases per day per 100,000 residents in Placer County during the past week, the most of the four counties in Sacramento with available data.

Case growth in the Sacramento metro area varies at the county level. In El Dorado County, for example, there were an average of 24.4 new cases per day per 100,000 residents in the past week — the least of any county in Sacramento and more than the case growth rate in Placer County.

While Placer County is driving the growth of COVID-19 in the Sacramento area, it does not have the highest incidence of cases overall. As of September 16, there were a total of 8,471.6 confirmed cases per 100,000 residents in Placer County, the second most of the four counties in the metro area. For comparison, the U.S. has so far reported 12,697.8 cases per 100,000 Americans nationwide.

In order to slow the spread of COVID-19, city and county governments have ordered the closure of thousands of consumer-facing businesses. These measures have led to widespread job loss and record unemployment. In Placer County, unemployment peaked at 13.0% in April 2020. As of June 2021, the county’s unemployment rate was 5.4%.

To determine the county in every metropolitan area where COVID-19 is growing the fastest, 24/7 Wall St. compiled and reviewed data from state and local health departments. We ranked counties according to the average number of new daily COVID-19 cases per 100,000 residents in the seven days ending September 16. To estimate the incidence of COVID-19 at the metropolitan level, we aggregated data up from the county level using boundary definitions from the U.S. Census Bureau. Population data used to adjust case and death totals came from the U.S. Census Bureau’s 2019 American Community Survey and are five-year estimates. Unemployment data is from the Bureau of Labor Statistics and is not seasonally adjusted.

These are all the counties in California where COVID-19 is slowing (and where it’s still getting worse).

Rank in MSA	County	Population	New daily cases per 100,000, week ending September. 16	New daily cases per 100,000, week ending September. 9	Cumulative cases per 100,000	Cumulative deaths per 100,000
1	Placer County	385,512	41.9	66.3	8,471.6	89.2
2	Sacramento County	1,524,553	38.3	67.9	9,480.6	133.7
3	Yolo County	217,352	30.9	37.1	8,283.3	110.0
4	El Dorado County	188,563	24.4	51.3	7,527.5	64.7

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