Cumberland is a town in Hancock and Marion counties, Indiana, United States. The population was estimated to be at 6,419 as of the 2023 census up from 5,169 in 2010. Cumberland was founded in the 1830s when the Cumberland Road was extended to that point. Cumberland contained a post office from 1834 until it was discontinued in 1958. Since 1970, th…Cumberland is a town in Hancock and Marion counties, Indiana, United States. The population was estimated to be at 6,419 as of the 2023 census up from 5,169 in 2010. Cumberland was founded in the 1830s when the Cumberland Road was extended to that point. Cumberland contained a post office from 1834 until it was discontinued in 1958. Since 1970, the Marion County portion of Cumberland has been subject to Unigov as an included town.