Mahaska is located approximately 10 miles north of US Hwy 36 via county roads in Washington County.  The city was founded in 1887 by L. Bonham and named after Chief Mahaska of the Iowa Indians.

The Sixth Principal Meridian or 40th Parallel Marker, which is located 1 mile west and 1 mile north of Mahaska on the Kansas/ Nebraska line.  Marked in 1854, this surveyor’s point is the site from which more than 200 million miles of land was surveyed for the states of Kansas, Nebraska, Wyoming, Colorado and South Dakota.  The original marker came about on May 30, 1854, as Congress agreed to establish and survey the Kansas and Nebraska territories.  They agreed the 40 degree parallel should be the base line and that Kansas would be a slave territory and Nebraska free.  A piece of the original marker was discovered in 1976 and in 1987 a beautiful granite marker was placed by the Professional Surveyor’s organization and continues to be kept-up by that organization.