Harlan is an unincorporated census-designated place in Springfield Township, Allen County, Indiana, United States. As of the 2010 census, Harlan had a population of 1,634. Present-day Harlan originally consisted of two communities, Harlan and Maysville. The border between the two towns was Georgetown Road, with Harlan being on the north side of the road.Maysville faded from existence when the post office was built in Harlan sometime around the turn of the 20th century.