Flathead Lake is a large natural freshwater lake located in northwest Montana, United States. It is the largest natural freshwater lake west of the Mississippi River in the contiguous United States. The lake covers an area of about 197 square miles (510 square kilometers) and has a maximum depth of about 370 feet (113 meters). It is approximately 28 miles (45 kilometers) long and 15 miles (24 kilometers) wide.

The lake is situated at the foot of the Mission Mountains and the Flathead National Forest, making it a popular destination for outdoor activities such as fishing, boating, camping, hiking, and wildlife watching. The lake is home to a variety of fish species, including lake trout, whitefish, yellow perch, and bull trout, making it a popular fishing spot.

Flathead Lake is also surrounded by several state parks, wildlife refuges, and scenic byways that provide visitors with stunning views of the lake and the surrounding landscape. Wild Horse Island, located in the middle of the lake, is a popular destination for hikers, boaters, and wildlife enthusiasts, as it is home to a variety of wildlife such as bighorn sheep, mule deer, bald eagles, and wild horses.

Overall, Flathead Lake is a beautiful destination that offers a variety of recreational activities and scenic views, making it a popular spot for locals and tourists alike.