Nicollet County, named in honor of Joseph N. Nicollet, a French explorer, lies in south central Minnesota and closely resembles an isosceles triangle with 104.6 miles of Minnesota River front. Within the 280,866.22 total acres in the County, almost 245,000 acres is farmland with 24,000 acres of forest land and 12,000 acres of wetland. The County is composed of 5 cities and 13 townships.

In order to establish the County, the Territorial Governor appointed the following Nicollet County officers: Register of Deeds, County Treasurer, Sheriff, and three County Commissioners. The first Board meeting was held on June 27, 1853 at the hall in Traverse de Sioux.

The first county election was held on October 11, 1853 to fill the following offices: three County Commissioners, Sheriff, Register of Deeds, County Treasurer, two Constables, three Assessors, Judge of Probate, District Attorney, and Court Surveyor.

The County Commissioners originally established nine townships in Nicollet County. Several years later, four more townships were created.

The state capitol was nearly moved to St. Peter from St. Paul. However, Joseph Rollette absconded with the bill that would make St. Peter the state capitol, and returned to St. Paul 123 as the gavel sounded the end of the legislative session.

In 1856, a petition was submitted to move the County Courthouse from Traverse des Sioux to St. Peter. The petition was thrown out because some names were duplicates, some were non-residents, and some were deceased persons, along with other various reasons. In 1858, the petition was resubmitted and passed by a vote of 457 to 301, and the Courthouse was built in St. Peter.

Construction of the present Courthouse was started in 1880 and completed the following year. An addition to the Courthouse was built in 1976. Following damage from a tornado in March of 1998, a remodeling and addition project took place in 1999/2000.

By 1859, there were 15 school districts in Nicollet County, and the first railroad came St. Peter in 1868