Rensselaer is a village in Ralls County, Missouri, United States.

[6] A post office called Rensselaer was established in 1871, and remained in operation until 1953.

[7] St. Peter's Catholic Church was listed on the National Register of Historic Places in 1980.

There were 87 housing units at an average density of 44.4 per square mile (17.1/km2).

17.9% of all households were made up of individuals, and 3.8% had someone living alone who was 65 years of age or older.

12.5% of all households were made up of individuals, and 4.2% had someone living alone who was 65 years of age or older.

None of the families and 4.4% of the population lived below the poverty line, including those under eighteen and those over 64.