Marysburg is an unincorporated community in Blue Earth and Le Sueur counties in the U.S. state of Minnesota.The center of Marysburg is generally considered near the intersection of 243rd Street (County 16) and John Street. The junction of Le Sueur County Road 15 and Blue Earth County Road 26 is nearby.Marysburg is located within Jamestown Township in Blue Earth County; and also located within Washington Township in Le Sueur County. From 1858 to 1903, the community had a post office.