Monroe Lake is a reservoir located about 10 miles (16 km) southeast of Bloomington, Indiana, United States.

The lake is the largest entirely situated in Indiana with 10,750 acres (43.5 km2) of water surface area spread over the counties of Monroe and Brown.

It is also home to 13,202 acres (53.43 km2) of protected forest and three recreational areas (Fairfax, Hardin Ridge, and Paynetown).

The reservoir provides abundant fishing throughout the year, and recreational opportunities such as boating and water skiing attract visitors from throughout Indiana and the Midwest.

[4] The lake was designed as a primary water source for the City of Bloomington and to prevent flood damage downstream.