Farm Island is a 2054 acre lake in Aitkin county. It has 12.6 miles of shoreline. The lake has a maximum depth of 56 feet. Water clarity in 2004 was 15 feet.
The Ripple River (at one time called the Mud River) flows into the lake on the west side and out on the northeast. It flows through a number of lakes and empties into the Mississippi in Aitkin.
There are 3 islands on the lake. The largest is Farm Island at 29 acres. It gets its name from the Ojibways that had large farm fields on the island prior to 1900.