Hamilton is a city in Marion County, Iowa, United States.

[3] According to the United States Census Bureau, the city has a total area of 0.54 square miles (1.40 km2), all of it land.

There were 56 housing units at an average density of 110.6 per square mile (42.7/km2).

There were 54 housing units at an average density of 100.0 per square mile (38.6/km2).

24.5% of all households were made up of individuals, and 12.3% had someone living alone who was 65 years of age or older.

There were 55 housing units at an average density of 101.5 per square mile (39.2/km2).

28.3% of all households were made up of individuals, and 18.9% had someone living alone who was 65 years of age or older.

There were 5.1% of families and 10.5% of the population living below the poverty line, including 9.1% of under eighteens and 11.1% of those over 64.