Union Pier is an unincorporated community in Berrien County in the U.S. state of Michigan. It is situated between the Lake Michigan shore and the Galien River about five miles north of the Indiana state border. The ZIP code is 49129 and the FIPS place code is 81400. After the end of World War II, many Lithuanian immigrants began settling in Union Pier. Although few Lithuanian-Americans remain today, several Lithuanian facilities remain, such as Milda's Corner Market and Gintaras Resort.