Crystal Lake, the largest lake with this name in Michigan, is located near Lake Michigan in Benzie County. It is about 25 miles (40 km) southwest of Traverse City and approximately 2 miles (3.2 km) northeast of Frankfort. Its coordinates are 44°39′N 86°09′W (44.650°N 86.150°W). The lake is about 2.5 by 8 miles (4.0 by 12.9 km) in size and has a maximum depth of 165 feet (50 m). Covering 9,854 acres (40 km²), it is Michigan’s ninth largest inland lake. Before the American Civil War, Crystal Lake was called "Cap Lake" because whitecaps often appeared on its surface. The lake is next to the southern part of the Sleeping Bear Dunes National Lakeshore.

In 1873, people tried to connect Crystal Lake to Lake Michigan by digging a channel. At the time, Crystal Lake’s water level was higher than Lake Michigan’s. When the channel was opened, the water level in Crystal Lake dropped about 20 feet (6.1 m). Although the project did not succeed, the lower water level revealed sandy beaches, including the public beach at Beulah.

The area that drains water into Crystal Lake is small, and there is very little fertilizer or sewage flowing into the lake. This results in the lake’s very clear water, which is why it is named Crystal Lake. The lake’s surface covers 35% of the total area of its drainage basin, which includes both land and water.