Redstone Lake is a lake located in geographic Guilford Township in the Municipality of Dysart et al, Haliburton County in Central Ontario, Canada.

[1][2] It is in the Great Lakes Basin and is part of the Gull River system.

There are two primary outflows that are both controlled by dams and that both lead to the Gull River.

The East Redstone River at the southeast leads to Eagle Lake further downstream, and the Redstone River at the southwest leads to Green Lake further downstream.

Since the Gull River system flows to the summit of the waterway at Balsam Lake, its tributaries including Redstone Lake serve as an important water flow control reservoir.