The park is located approximately 150 km northwest of Vancouver or 60 km northwest of Pemberton at the headwaters of the Lillooet River.
To reach Upper Lillooet Park, visitors drive to Pemberton and then along the Upper Lillooet forest service road on the north side of the Lillooet River, approximately 70 km to the boundary of the park. The road ends just outside the park boundary. Rough logging roads extend up Meager Creek towards the south end, but not into, the park. Helicopter access, with a valid permit, has been moderately popular mostly for accessing base camp areas in the alpine portions of the park.