Marne is a city in Cass County, Iowa, United States. The population was 149 at the 2000 census.
Marne got its beginnings when in 1875 when German investors from a settlement in Davenport, Iowa filed papers and plotted the land purchased from Thomas Meredith. The city's name origins came from a city in Germany called Marne.
Marne is located at 41°26′55″N 95°6′43″W / 41.44861°N 95.11194°W / 41.44861; -95.11194 (41.448586, -95.111919). According to the United States Census Bureau, the city has a total area of 0.6 square miles (1.5 km²), all of it land.