Mahaska County was formed on February 17, 1843. The county has been self-governing since February 5, 1844.
It was named after Chief Mahaska of the Iowa tribe.
The county was the first in Iowa to have a sheriff and a justice of peace.
The first courthouse was completed in January, 1846. The second structure was put into use on February 27, 1886.
The first school, a small log cabin one-half mile east of Oskaloosa, was opened on September 16, 1844 and the Cumberland Presbyterian Church opened as the first church in 1846.
On July 2, 1850, the first edition of the Iowa Herald was issued (today the Oskaloosa Herald).
In 1864, the first tracks were laid through the county of the Des Moines Valley Railroad.
Coal mining was once a major industry in Mahaska County. In the 19th century, Muchakinock, about 5 miles south of Oskaloosa, was probably the largest and most prosperous coal camp in Iowa.
County Seat: Oskaloosa
Mahaska County’s population: 22,181 (from the July 1, 2016 estimate of the Census Bureau.)
