Junction of highway # 89 - City of Custer, South Dakota North to Sylvan Lake, South Dakota. Access to U.S. Highways # 16 & # 385. For highway travel North and south via U.S. Highway # 385 - See Milebymile.com Road Map Highway Travel Guides U.S. Highway # 385 north - City of Custer to Deadwood City, SD. or south - City of Hot Springs, SD. to city of Custer, SD Black Hills National Forest - Custer State Park To City of Custer Black Hills National Forest stretches for 1.2 million acres, offering outdoor adventure like hiking, biking and camping amidst stunning scenery. Find grassy mountain meadows, towering granite peaks, deep canyons, cascading trout streams and clear, clean lakes.