I went through the
New York Times' 2010 Census map, trying to find all of the population living in census tracts in the Midwest over 10,000 people per square mile. The outlier is not surprising, but number two might be.
The top eleven metros:
Chicago - 2,584,931
Milwaukee - 252,711
Minneapolis-St. Paul -183,441
Cleveland - 98,090
Detroit - 70,371 (not counting Windsor)
St. Louis - 64,143
Columbus - 38,613
Madison - 36,029
Cincinnati - 34,703
Ann Arbor: 23,663
Champaign-Urbana: 23,331
The full list:
Illinois:
Champaign-Urbana: 23,331 (UI campus, including a 49,162 ppsm tract)
Chicago area: 2,584,931 (2,138,426 in city of Chicago)
DeKalb: 6,016 (Northern IL campus)
Normal: 7,036 (IL State campus)
Indiana:
Bloomington: 11,555 (IU campus)
Lafayette: 15,128 (Purdue campus in West Lafayette)
Iowa:
Iowa City: 14,985 (UI campus)
Kansas:
Lawrence: 7,637 (UK campus)
Manhattan: 2,642 (KSU campus)
Michigan:
Ann Arbor: 23,663 (UM campus)
Detroit: 70,371 (53,999 in Detroit, 14,272 in Hamtramck, 2,100 in Southfield)
Grand Rapids: 3,187 (south of downtown along 131, and several other tracts just shy)
Lansing: 17,028 (MSU campus in East Lansing)
Minnesota:
Duluth: 4,239 (just east of downtown)
Minneapolis-St. Paul: 183,441 (141,639 in Minneapolis, 37,304 in St. Paul, 4,498 in Brooklyn Park)
Missouri:
Columbia: 6,753 (UM campus)
Kansas City: 2,998 (Crown Plaza)
Springfield: 4,580 (MSU campus)
St. Louis: 64,143 (15,055 Central West End, 49,088 on South Side)
Nebraska:
Lincoln: 16,628 (UN campus)
Omaha: 2,859 (west of downtown, several others just under 10,000 ppsm)
Ohio:
Akron - 1,448 (U of Akron campus)
Athens - 9,956 (OU campus)
Cincinnati - 34,703 (23,992 in the Over-the-Rhine area, 10,711 in Covington, KY)
Cleveland - 98,090 (63,312 in Cleveland, 27,087 in Lakewood, 6,052 in Euclid, 1,639 in East Cleveland)
Columbus - 38,613 (OSU campus)
Dayton - 3,481 (south of downtown)
Kent - 7,117 (Kent State campus)
Oxford - 5,265 (Miami campus)
Wisconsin:
Madison: 36,029 (the isthmus)
Milwaukee: 252,711 (240,688 in Milwaukee, 7,487 in West Allis, 4,536 in Cudahy)
Sheboygan - 2,912 (northwest of downtown)
For Indianapolis, the closest census tract is the east half of downtown within the I-65 loop, at 8,099 ppsm.
The total population in the Midwest in tracts over 10,000 people per square mile is 3,548,869, of which 72.5% lives in the Chicago metro area.
Bonus: Kentucky
Lexington: 4,904 (heart of UK campus)
Louisville: 6,570 (a small cluster just south of downtown less than 11,000 ppsm)