Greendale is a city in St. Louis County, Missouri, United States.

[5] According to the United States Census Bureau, the city has a total area of 0.21 square miles (0.54 km2), all land.

There were 329 housing units at an average density of 1,566.7 per square mile (604.9/km2).

40.7% of all households were made up of individuals, and 11.5% had someone living alone who was 65 years of age or older.

33.8% of all households were made up of individuals, and 8.2% had someone living alone who was 65 years of age or older.

Police services are provided by contract with the neighboring city of Normandy.