Lake Sumner is a census-designated place (CDP) in De Baca County, New Mexico, United States.

U.S. Route 84 forms the northeastern edge of the CDP; the highway leads southeast 10 miles (16 km) to Fort Sumner, the De Baca County seat, and northwest 34 miles (55 km) to Santa Rosa.

34.1% of all households were made up of individuals, and 13.6% had someone living alone who was 65 years of age or older.

There were no families and 10.5% of the population living below the poverty line, including no under eighteens and 45.5% of those over 64.

[9] Media related to Lake Sumner, New Mexico at Wikimedia Commons