Fish Lake Township is a township in Chisago County, Minnesota, United States. The population was 2,012 at the 2010 census. Fish Lake Township was organized in 1868. It took its name from Fish Lake. The township is located in northwest Chisago County and is bordered to the west and south by Isanti County. To the east is the city of Harris. The unincorp…Fish Lake Township is a township in Chisago County, Minnesota, United States. The population was 2,012 at the 2010 census. Fish Lake Township was organized in 1868. It took its name from Fish Lake. The township is located in northwest Chisago County and is bordered to the west and south by Isanti County. To the east is the city of Harris. The unincorporated community of Stark is in the southeast part of the township.