Pennington County, Minnesota: History
The Wisconsin Territory was established by the federal government effective July 3, 1836, and existed until its eastern portion was granted statehood (as Wisconsin) in 1848. The federal government set up the Minnesota Territory in the remaining territory, effective March 3, 1849. The newly organized territorial legislature created nine counties across the territory in October of that year. One of those original counties, Pembina, had its lower portion partitioned in 1858 by the newly organized Minnesota State legislature to create Polk County. On December 24, 1896, the legislature partitioned the northern portion of Polk to create Red Lake County. Then on November 23, 1910, the northern part of Red Lake was sectioned off to create Pennington County, the penultimate Minnesota county to be created (followed by Lake of the Woods in 1922). The county was named for Edmund Pennington (1848-1926), a longtime Minnesota railroad executive, who was serving as president of the Minneapolis, St. Paul, and Sault Ste. Marie Railway when the county was formed. Thief River Falls, the area's major settlement (platted in 1887), was specified as the county seat.