Union County, Illinois

Founding: 1818
Parent county: Johnson

Namesake: A traditional name
Seat: Jonesboro (1818–)

Land area: 413 square miles

Population (2020): 17,244

Population (historic): 2,362 (1820); 7,615 (1850); 16,518 (1870); 22,610 (1900); 19,883 (1930)

Periods of population growth: pre-1820–1900; 1930s; 1970s; 1990s

Subdivisions: Two cities; four villages

Pre-1940 residences (estimated): 1,708 (21.4%)
Pre-1940 housing survival rate: 39.3%
Pre-1860 housing survival rate (1940): 5.3%

Farm housing in disrepair (1950): 13.6%

Nonfarm housing in disrepair (1950): 13.1%

Average farmhouse value (1930): $1,000
Average outbuilding value (1930): $755

Average farmhouse size (1940): 4.7 rooms
Number of farms (1920): 2,006
Average farm size (1920): 74.8 acres
Sources of settlement: Tennessee, North Carolina, Kentucky, and Germany
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Jonesboro

Namesake: Unclear—presumably an early resident

Founding: 1818 (platting); 1823 (post office); 1857 (incorporation)

Population (2020): 1,711

Population (historic): 584 (1850); 1,108 (1870); 1,130 (1900); 1,241 (1930)

Periods of population growth: pre-1850–1870; 1900s; 1920–1980; 1990s
Pre-1940 residences (estimated): 193 (22.3%)
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Outstanding Buildings

1. St. Paul's Lutheran Church (1860–1861/1889). Kornthal Church Road, west of State Route 127. Italianate.
2. Zachary Cook House (c. 1895). 2160 State Route 146. Eastlake.

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