Greenleaf is a city in Washington County, Kansas, United States.

[6] The post office at Round Grove, Kansas; which had been known at various times as Prospect Hill and Hopper, was moved to Greenleaf when the railroad missed the settlement.

[9] According to the United States Census Bureau, the city has a total area of 0.46 square miles (1.19 km2), all land.

[10] The 2020 United States census counted 350 people, 142 households, and 91 families in Greenleaf.

There were 155 housing units at an average density of 342.9 per square mile (132.4/km2).

31.0% of households consisted of individuals and 19.0% had someone living alone who was 65 years of age or older.

There were 199 housing units at an average density of 432.6 per square mile (167.0/km2).

48.5% of all households were made up of individuals, and 18.1% had someone living alone who was 65 years of age or older.

There were 202 housing units at an average density of 435.7 per square mile (168.2/km2).

50.3% of all households were made up of individuals, and 29.8% had someone living alone who was 65 years of age or older.

[25] The Washington County High School mascot is Tigers.