Spencerville, IndianaSpencerville is an unincorporated community located in Spencer Township, DeKalb County, Indiana, United States. Spencerville is home to the county's only covered bridge.HistoryThe Spencerville post office was established in 1839. Spencerville was named after John Spencer, who was a relative of one of the city's founders.DemographicsThe United [States Census Bureau] defined Spencerville as a census designated place in the 2022 American Community Survey.