St. Mary Lake is a picturesque glacial lake located in Glacier National Park in Montana, USA. It spans approximately 3.5 miles in length and is surrounded by stunning mountain scenery, making it a popular destination for visitors and photographers alike. The lake is known for its striking blue color, which is a result of glacial silt suspended in the water. The lake is also home to various wildlife, including bald eagles and moose, and offers recreational activities such as hiking, fishing, and boating. The Going-to-the-Sun Road, a scenic highway, provides access to the lake and showcases the breathtaking landscapes of the park.