Spencer is a village in Marathon County, Wisconsin. It is part of the Wausau, Wisconsin Metropolitan Statistical Area. The population was 1,925 at the 2010 census. The village, which lies between two marshes was founded in 1874 at a branch on the Wisconsin Central Railway. Today it sits at the crossroads of Wisconsin Highway 13 and WIS 98 and se…Spencer is a village in Marathon County, Wisconsin. It is part of the Wausau, Wisconsin Metropolitan Statistical Area. The population was 1,925 at the 2010 census. The village, which lies between two marshes was founded in 1874 at a branch on the Wisconsin Central Railway. Today it sits at the crossroads of Wisconsin Highway 13 and WIS 98 and serves as the terminus of several Marathon County Trunk Highways. Spencer lies about 8 miles northwest of Marshfield, along WIS 13.