| Crystal Lake | |
| Pushpin Map: | USA Montana |
| Pushpin Map Caption: | Location in Montana |
| Coords: | 46.7998°N -109.5141°W |
| Type: | Natural/Fresh Water Lake |
| Inflow: | Big Rock Creek |
| Outflow: | Big Rock Creek |
| Basin Countries: | United States |
| Length: | 3250feet |
| Width: | 1070feet |
| Area: | 45.7acres |
| Max-Depth: | 15feet |
| Elevation: | 6014feet |
Crystal Lake is a 45acres body of water in the Big Snowy Mountains in Fergus County, Montana, United States. The lake is located 18 miles south of Lewistown in the Lewis and Clark National Forest. The Forest Service's Crystal Lake Campground is located at the lake's southern tip. The lake is stocked annually with rainbow trout.Crystal Lake offers camping, hiking, and fishing located in an island of wild mountains surrounded by prairie. The lake is in the Big Snowy Mountains which are one of the small “island” ranges that dot central Montana.