Adams County, Illinois

Founding: 1825
Parent county: Pike

Namesake: John Quincy Adams, U.S. president
Seat: Quincy (1825–)

Land area: 855 square miles

Population (2020): 65,737

Population (historic): 2,186 (1830); 26,508 (1850); 56,362 (1870); 67,058 (1900); 62,784 (1930)

Periods of population growth: pre-1830–1900; 1920–1940; 1950–1980; 1990s

Subdivisions: One city; 13 villages; 23 townships

Pre-1940 residences (estimated): 8,080 (26.7%)
Pre-1940 housing survival rate: 50.2%
Pre-1860 housing survival rate (1940): 13.3%

Farm housing in disrepair (1950): 5.1%

Nonfarm housing in disrepair (1950): 6.2%

Average farmhouse value (1930): $1,719
Average outbuilding value (1930): $1,514

Average farmhouse size (1940): 6 rooms
Number of farms (1920): 3,844
Average farm size (1920): 97.1 acres
Sources of settlement: Germany, Ohio, Pennsylvania, Kentucky, Ireland, New York, Virginia, and Tennessee
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Quincy

Namesake: John Quincy Adams, U.S. president

Founding: 1825 (platting); 1826 (post office); 1839 (incorporation)

Population (2020): 39,463

Population (historic): 2,319 (1840); 13,718 (1860); 27,268 (1880); 36,252 (1900); 39,241 (1930)

Periods of population growth: pre-1840–1910; 1920–1970; 1990–2010
Pre-1940 residences (estimated): 5,877 (30.6%)
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