Oskaloosa is a city in and the county seat of Jefferson County, Kansas, United States. As of the 2010 census, the city population was 1,113.
Oskaloosa was founded in 1856. It was named after the city of Oskaloosa, Iowa. The first post office in Oskaloosa was established in November 1856.
In 1888, Oskaloosa citizens elected Mary D. Lowman mayor with a city council composed entirely of women, making the city the first in the state to elect an all-women city administration.
Oskaloosa is located at 39°12′57″N 95°18′50″W (39.215849, -95.313800). It is at the intersection of U.S. Route 59 and K-92, approximately 15 miles north of Lawrence. According to the United States Census Bureau, the city has a total area of 1.03 square miles (2.67 km2), of which, 1.02 square miles (2.64 km2) is land and 0.01 square miles (0.03 km2) is water.
The climate in this area is characterized by hot, humid summers and generally cold winters. According to the Köppen Climate Classification system, Oskaloosa has a humid subtropical climate, abbreviated "Cfa" on climate maps.
Oskaloosa is part of the Topeka, Kansas Metropolitan Statistical Area.
As of the census of 2010, there were 1,113 people, 435 households, and 281 families living in the city. The population density was 1,091.2 inhabitants per square mile (421.3/km2). There were 480 housing units at an average density of 470.6 per square mile (181.7/km2).