Reserve is a city in Brown County, Kansas, United States.

A post office was opened in Reserve in 1882, and remained in operation until it was discontinued in 1983.

[5] According to the United States Census Bureau, the city has a total area of 0.11 square miles (0.28 km2), all land.

[6] The 2020 United States census counted 67 people, 36 households, and 18 families in Reserve.

There were 50 housing units at an average density of 434.8 per square mile (167.9/km2).

44.4% of households consisted of individuals and 22.2% had someone living alone who was 65 years of age or older.

There were 58 housing units at an average density of 527.3 per square mile (203.6/km2).

33.3% of all households were made up of individuals, and 11.1% had someone living alone who was 65 years of age or older.

48.0% of all households were made up of individuals, and 22.0% had someone living alone who was 65 years of age or older.

There were 6.7% of families and 24.7% of the population living below the poverty line, including no under eighteens and 42.9% of those over 64.