Mount Summit is a town in Prairie Township, Henry County, Indiana, United States. The population was 352 at the 2010 census.
Mount Summit was platted in 1854. It was named for its lofty elevation. A post office has been in operation in Mount Summit since 1869.
Mount Summit is located at 40°0′14″N 85°23′8″W (40.003921, -85.385497).
According to the 2010 census, Mount Summit has a total area of 0.19 square miles (0.49 km2), all land.
As of the census of 2010, there were 352 people, 139 households, and 96 families residing in the town. The population density was 1,852.6 inhabitants per square mile (715.3/km2). There were 152 housing units at an average density of 800.0 per square mile (308.9/km2). The racial makeup of the town was 97.2% White, 0.3% Native American, 0.6% from other races, and 2.0% from two or more races. Hispanic or Latino of any race were 2.3% of the population.
There were 139 households of which 36.0% had children under the age of 18 living with them, 51.1% were married couples living together, 12.9% had a female householder with no husband present, 5.0% had a male householder with no wife present, and 30.9% were non-families.