LaSalle County, Illinois

Founding: 1831
Parent counties: Putnam and unorganized territory

Namesake: René-Robert Cavelier, Sieur de La Salle, French explorer
Seat: Ottawa (1831–)

Land area: 1,135 square miles

Population (2020): 109,658

Population (historic): 9,348 (1840); 48,332 (1860); 70,403 (1880); 87,776 (1900); 97,695 (1930)

Periods of population growth: pre-1840–1980; 1990–2010

Subdivisions: Eight cities; 24 villages; two CDPs; 37 townships

National Register listings: 32

Pre-1940 residences (estimated): 14,738 (29.4%)
Pre-1940 housing survival rate: 61%
Pre-1860 housing survival rate (1940): 34.9%

Farm housing in disrepair (1950): 5.8%

Nonfarm housing in disrepair (1950): 4.4%

Average farmhouse value (1930): $2,335
Average outbuilding value (1930): $2,865

Average farmhouse size (1940): 7.3 rooms
Number of farms (1920): 4,213
Average farm size (1920): 143.1 acres
Sources of settlement: New York, Ireland, Germany, Pennsylvania, Ohio, England, Norway, and Massachusetts
_________________________________________________________________________________

Ottawa

Namesake: The Ottawa people

Founding: 1830 (platting); 1832 (post office); 1853 (incorporation)

Population (2020): 18,840

Population (historic): 7,736 (1870); 9,985 (1890); 9,535 (1910); 15,094 (1930)

Periods of population growth: pre-1870–1900; 1910–1960; 1990–2020
Pre-1940 residences (estimated): 2,627 (29.8%)
_________________________________________________________________________________

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

Outstanding Buildings

1. House (c. 1845). 1980 35th Road. Dayton. Greek Revival.
2. Annunciation Catholic Church (1924). 1203 State Route 18. Eagle. Gothic Revival.
3. *William Gentleman House (c. 1855). 1830 2703rd Road. Fall River.
4. Herman Knoll Farm (c. 1905). 1895 2703rd Road. Fall River. Classical Revival/Queen Anne.
5. Henry Wollenhaupt Farm (c. 1880). 2294 18th Road. Grand Rapids. Italianate.
6. Francis Bowen Farm (c. 1880). 4002 2750th Road. Mission. Italianate.
7. *The Oaks / William Wallace House (1858–1860). 2101 Caton Road. Ottawa. Gothic Revival.
8. *Sts. Peter and Paul Catholic Church (1872). 3888 1st Road. Troy Grove.
9. *Spring Valley House (c. 1849). 1042 27th Road. Utica. Greek Revival.