Rio en Medio is a census-designated place (CDP) in Santa Fe County, New Mexico, United States.

It is part of the Santa Fe, New Mexico Metropolitan Statistical Area.

According to the United States Census Bureau, the CDP has a total area of 0.4 square miles (1.0 km2), all land.

There were 43 housing units at an average density of 97.5 per square mile (37.6/km2).

12.5% of all households were made up of individuals, and none had someone living alone who was 65 years of age or older.