Iron Mountain Lake is a city in St. Francois County, Missouri, United States.

There were 367 housing units at an average density of 187.2 per square mile (72.3/km2).

25.8% of all households were made up of individuals, and 11.2% had someone living alone who was 65 years of age or older.

There were 380 housing units at an average density of 192.9 per square mile (74.5/km2).

The racial makeup of the city was 98.12% White, 0.14% Native American, 0.14% Asian, and 1.59% from two or more races.

24.2% of all households were made up of individuals, and 11.7% had someone living alone who was 65 years of age or older.