Gilman is a city in the southeastern corner of Marshall County, Iowa, United States. The population was 509 at the 2010 census.
Gilman got its start in the year 1870, following construction of the Central Railroad of Iowa through the territory. The town is named for Charles Gilman, a railroad contractor. Gilman was incorporated in 1876.
Gilman is located at 41°52′47″N 92°47′20″W (41.879750, -92.788786).
According to the United States Census Bureau, the city has a total area of 0.54 square miles (1.40 km2), all land.
At the 2010 census there were 509 people in 233 households, including 142 families, in the city. The population density was 942.6 inhabitants per square mile (363.9/km2). There were 253 housing units at an average density of 468.5 per square mile (180.9/km2). The racial makup of the city was 99.6% White, 0.2% from other races, and 0.2% from two or more races. Hispanic or Latino of any race were 0.8%.
Of the 233 households 28.8% had children under the age of 18 living with them, 48.1% were married couples living together, 11.6% had a female householder with no husband present, 1.3% had a male householder with no wife present, and 39.1% were non-families. 34.8% of households were one person and 15% were one person aged 65 or older.