After adding over 589,000 new cases throughout the last week, the U.S. now has more than 49.3 million confirmed cases of COVID-19. There have been more than 780,000 COVID-19-related deaths — the highest death toll of any country.

New cases continue to rise, albeit at a slowing rate. In the past week, there were an average of 9.8 daily new coronavirus cases per 100,000 Americans — a decrease from the week prior, when there were an average of 1508.1 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 Chicago-Naperville-Elgin, IL-IN-WI, metro area consists of Cook County, DuPage County, Lake County, and 11 other counties. In the past week, there were an average of 0.9 new coronavirus cases every day per 100,000 Chicago 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 0.9 daily new cases per 100,000 Chicago residents.

The spread of coronavirus depends on a variety of factors and can vary even between neighboring counties. Within the Chicago-Naperville-Elgin metro area, COVID-19 is growing the fastest in Cook County. There were an average of 15.6 new cases per day per 100,000 residents in Cook County during the past week, the most of the 14 counties in Chicago with available data.

Case growth in the Chicago metro area varies at the county level. In Kendall County, for example, there were an average of 5.6 new cases per day per 100,000 residents in the past week — the least of any county in Chicago and more than the case growth rate in Cook County.

While Cook County is driving the growth of COVID-19 in the Chicago area, it does not have the highest incidence of cases overall. As of December 14, there were a total of 13,411.4 confirmed cases per 100,000 residents in Cook County, the 10th most of the 14 counties in the metro area. For comparison, the U.S. has so far reported 15,206.9 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 Cook County, unemployment peaked at 18.1% in April 2020. As of June 2021, the county’s unemployment rate was 10.0%.

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 December 14. 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 Illinois 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 December 14	New daily cases per 100,000, week ending December 7	Cumulative cases per 100,000	Cumulative deaths per 100,000
1	Cook County	5,198,275	15.6	1,485.0	13,411.4	223.2
2	Kenosha County	168,524	12.6	1,594.4	16,382.2	248.6
3	Lake County	485,707	12.5	1,626.7	15,274.2	261.1
4	Kane County	531,376	12.1	1,561.6	14,345.0	171.4
5	Lake County	701,473	11.5	1,375.0	12,862.4	159.8
6	DuPage County	929,060	10.9	1,388.9	13,161.5	152.6
7	Will County	689,315	9.9	1,572.2	14,995.8	171.9
8	Newton County	13,992	9.5	1,216.7	13,400.5	378.8
9	Porter County	168,636	7.6	1,605.1	15,626.0	234.2
10	Grundy County	50,666	6.9	1,691.5	17,021.3	179.6
11	DeKalb County	104,366	6.6	1,364.0	13,444.0	140.9
12	McHenry County	307,714	6.6	1,336.7	13,372.5	113.1
13	Jasper County	33,447	6.4	1,701.3	18,946.4	281.0
14	Kendall County	126,054	5.6	1,495.5	14,788.9	95.2

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