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 Washington-Arlington-Alexandria, DC-VA-MD-WV, metro area consists of Fairfax County, Montgomery County, Prince George’s County, and 22 other counties. In the past week, there were an average of 21.7 new coronavirus cases every day per 100,000 Washington residents, less than the national figure. The metro area’s average daily case growth in the most recent week is essentially unchanged from the week prior, when there was an average of 19.9 daily new cases per 100,000 Washington residents.

The spread of coronavirus depends on a variety of factors and can vary even between neighboring counties. Within the Washington-Arlington-Alexandria metro area, COVID-19 is growing the fastest in Warren County, Virginia. There were an average of 75.9 new cases per day per 100,000 residents in Warren County during the past week, the most of the 25 counties in Washington with available data.

Case growth in the Washington metro area varies widely at the county level. In Manassas Park city, for example, there were an average of 1.1 new cases per day per 100,000 residents in the past week — the least of any county in Washington and far more than the case growth rate in Warren County.

While Warren County is driving the growth of COVID-19 in the Washington area, it does not have the highest incidence of cases overall. As of September 16, there were a total of 10,257.8 confirmed cases per 100,000 residents in Warren County, the fifth most of the 25 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 Warren County, unemployment peaked at 11.0% in April 2020. As of June 2021, the county’s unemployment rate was 4.0%.

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.

Click here to see all current COVID-19 data for Washington D.C.

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	Warren County	39,492	75.9	64.5	10,257.8	164.6
2	Madison County	13,170	59.7	36.9	6,066.8	129.1
3	Jefferson County	56,506	55.4	35.7	10,099.8	120.3
4	Culpeper County	51,101	54.6	47.4	10,997.8	137.0
5	Spotsylvania County	132,833	51.5	46.6	9,606.0	99.4
6	Fredericksburg city	28,622	51.4	47.9	9,342.5	87.3
7	Stafford County	146,773	42.4	47.1	9,644.8	62.0
8	Fauquier County	69,728	37.1	48.5	8,636.4	107.6
9	Clarke County	14,423	31.7	20.1	7,952.6	152.5
10	Rappahannock County	7,378	30.2	49.5	6,451.6	40.7
11	Charles County	159,428	28.9	31.8	8,205.6	142.4
12	District of Columbia	692,683	27.5	24.8	8,394.3	168.5
13	Prince William County	461,423	23.1	20.4	10,967.2	114.2
14	Frederick County	251,422	21.2	18.4	8,848.5	141.2
15	Loudoun County	395,134	21.0	16.3	7,948.4	72.6
16	Manassas city	41,174	20.2	14.5	11,293.5	119.0
17	Arlington County	233,464	19.8	13.9	7,370.3	111.8
18	Prince George’s County	908,670	19.4	18.6	10,364.5	181.3
19	Alexandria city	157,613	18.7	14.4	8,404.8	90.1
20	Falls Church city	14,128	18.1	14.4	3,510.8	56.6
21	Fairfax County	1,145,862	15.7	13.9	7,455.7	99.8
22	Montgomery County	1,043,530	12.8	13.2	7,462.2	159.4
23	Calvert County	91,511	11.4	16.3	5,303.2	99.4
24	Fairfax city	23,531	6.2	4.7	2,630.6	80.7
25	Manassas Park city	16,986	1.1	1.4	7,359.0	64.8

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