Sedan is an unincorporated community in Richland Township, DeKalb County, Indiana.
Originally named Lawrence, the town's post office was first established in 1854 and referred to as Iba (or Ida). Renamed Sedan P.O. in 1861, the post office was subsequently discontinued in 1908. The community was likely named after Sedan, in France.
Sedan is located at .
Sedan appeared as a separately-returned community in the 1870 Census, when it was reported to have a population of 176.