 Washington State Route 501

State Route 501 (SR 501, designated as the Erwin O. Rieger Memorial Highway) is a state highway in the southern part of the U.S. state of Washington.It is split into two sections in Clark County, a north–south alignment connecting Interstate 5 (I-5) in Vancouver to the Port of Vancouver and the Ridgefield National Wildlife Refuge, and a west–east alignment connecting Ridgefield to I-5.