Petroleum County, Montana

Founding: 1925
Parent county: Fergus

Namesake: Oil fields within the county
Seat: Winnett (1925–)

Land area: 1,655 square miles

Population (2020): 496

Population (historic): 2,045 (1930); 1,083 (1940)

Periods of population growth: 1910–1930

Subdivisions: One town

National Register listings: Four

Pre-1940 residences (estimated): 128 (42.4%)
Pre-1940 housing survival rate: 21.8%

Farm housing in disrepair (1950): 15.7%

Nonfarm housing in disrepair (1950): 14.1%
Average farmhouse value (1930): $514
Average outbuilding value (1930): $638
Average farmhouse size (1940): 3.8 rooms
Sources of settlement: Montana, Iowa, and Minnesota
_________________________________________________________________________________

Winnett

Namesake: Walter Winnett, owner of the town site

Founding: 1910 (platting); 1910 (post office)

Population (2020): 188

Population (historic): 316 (1920); 408 (1930)

Periods of population growth: 1910–1930
Pre-1940 residences (estimated): 64 (47.8%)

_________________________________________________________________________________