It sits at latitude of 48.837 and longitude of -122.138. The elevation of Kulshan is 390 feet. It is just east of Welcome. It is at the base of the North Cascades, part of the Cascade Range, and slightly west of Mount Baker. The town can only be accessed on road by Mosquito Lake Road, which crosses over the North Fork Nooksack River from the Welcome entrance or at Acme in the south.