New Amsterdam is a town located in Washington Township, Harrison County, Indiana, United States, along the Ohio River. As of the 2020 census, the city population was 12. As of the 2020 Census, New Amsterdam was the smallest city, town, or Census Designated Place in the state of Indiana. River Forest was the smallest in 2010 when it had 22, but had risen to 26. New Amsterdam now officially became the smallest town in Indiana with the population being 12, down from 27 in 2010.

Harrison County is located in the far southern part of the U.S. state of Indiana along the Ohio River. The county was officially established in 1808. Its population was 39,654 as of the 2020 United States Census. Its county seat is Corydon, the former capital of Indiana.