Warren County, Illinois

Founding: 1831 (declared in 1825)
Parent county: Unorganized territory

Namesake: Joseph Warren, Boston revolutionary leader
Seat: Monmouth (1831–)

Land area: 542 square miles

Population (2020): 16,835

Population (historic): 308 (1830); 8,176 (1850); 23,174 (1870); 23,163 (1900); 21,745 (1930)

Periods of population growth: 1830–1870; 1890–1910; 1920s; 1940s; 1960–1980

Subdivisions: One city; four villages; 15 townships

National Register listings: 11

Pre-1940 residences (estimated): 3,214 (41.8%)
Pre-1940 housing survival rate: 51.9%
Pre-1860 housing survival rate (1940): 10.2%

Farm housing in disrepair (1950): 4.7%

Nonfarm housing in disrepair (1950): 8.7%

Average farmhouse value (1930): $2,401
Average outbuilding value (1930): $2,223

Average farmhouse size (1940): 6.8 rooms
Number of farms (1920): 1,899
Average farm size (1920): 142.5 acres
Sources of settlement: Ohio, Pennsylvania, New York, Sweden, Indiana, Kentucky, and Ireland
_________________________________________________________________________________

Monmouth

Namesake: Monmouth County, New Jersey

Founding: 1831 (platting as Kosciusko); 1841 (post office); 1852 (incorporation)

Population (2020): 8,902

Population (historic): 797 (1850); 4,662 (1870); 5,936 (1890); 9,128 (1910); 8,666 (1930)

Periods of population growth: pre-1850–1910; 1920–1970; 1990s
Pre-1940 residences (estimated): 1,591 (41.8%)
_________________________________________________________________________________



View and filter the data. Or see a larger map.
_________________________________________________________________________________

Outstanding Buildings

1. *Franklin Snapp Farm (c. 1855). 514 Wolf Road. Greenbush. Greek Revival. Razed.
2. *Pleasant Green School (1909). 235th Road and 1st Road. Hale. Classical Revival/Romanesque. Razed.
3. *Chapman Brooks Farm (c. 1870). 1100 192nd Road. Monmouth. Italianate.
4. *George Tucker Farm (1854). 521 85th Road. Roseville. Greek Revival.
5. *Hugh Martin House (c. 1860). 901 East Main Street. Sumner. Italianate.