Goat Lake is an alpine lake in Custer County, Idaho, United States, located high in the Sawtooth Mountains in the Sawtooth National Recreation Area. The lake is approximately 6 miles southwest of Stanley. The lake is most easily accessed from the Iron Creek trailhead, which can be accessed from State Highway 21 via Sawtooth National Forest ro…Goat Lake is an alpine lake in Custer County, Idaho, United States, located high in the Sawtooth Mountains in the Sawtooth National Recreation Area. The lake is approximately 6 miles southwest of Stanley. The lake is most easily accessed from the Iron Creek trailhead, which can be accessed from State Highway 21 via Sawtooth National Forest road 619.