Río San Juan (Spanish pronunciation: [ˈri.o saŋ ˈxwan]) is a department in Nicaragua.

It was formed in 1957 from parts of Chontales and Zelaya departments.

The department also includes the Solentiname Islands archipelago and the San Juan River, after which it is named.

Trinidad, in Río San Juan, is the most southerly point in Nicaragua.

This Nicaragua location article is a stub.