It is long and narrow and extends 102 kilometres (63 mi) east-northeast.

The Nelson River west channel enters the lake at the Jenpeg Dam and the Nelson River east channel enters near the communities of Cross Lake and Cross Lake First Nation.

The river then flows north to Sipiwesk Lake.

[4][5] The lake level is regulated by Manitoba Hydro at the Jenpeg Generating Station (54°32′36″N 98°1′36″W / 54.54333°N 98.02667°W / 54.54333; -98.02667 (Jenpeg)) at the southern end of the lake.

[6] From Moon Lake, the source of the Minago River, a portage led to South Moose Lake and the Saskatchewan River.