Whalen Island is located in Sand Lake which is the estuary of Sand Creek that starts at an elevation of 770 feet (235 m) in the Oregon Coast Range and flows generally south-southwest for 8 miles (13 km) to the Pacific Ocean draining a watershed of 10,880 acres (4,403 ha), about 13 miles (21 km) south-southwest of Tillamook and 5 miles (8 km) north of Pacific City, Oregon.