State Route 501 is a state highway

State highway

State highway, state road or state route can refer to one of three related concepts, two of them related to a state or provincial government in a country that is divided into states or provinces :#A...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Washington.

Segment 1

SR 501 starts at its southern terminus at Interstate 5

Interstate 5 in Washington

Interstate 5 in Washington is a highway in the U.S. state of Washington that extends from its border with Oregon to its border with Canada...

 in Vancouver, continuing west on Mill Plain Boulevard and north on Northwest Lower River Road to a wash-out west of Vancouver.

Segment 2

SR 501 resumes at the railroad tracks in Ridgefield and heads east on Pioneer Street to its northern terminus at I-5.

Major intersections

County	Location	Mile	Destinations	Notes
Clark Clark County, Washington Clark County is a county located in the southwestern part of the U.S. state of Washington, across the Columbia River from Portland, Oregon.Clark County was the first county of Washington, named after William Clark of the Lewis and Clark Expedition...	Vancouver Vancouver, Washington Vancouver is a city on the north bank of the Columbia River in the U.S. state of Washington. Incorporated in 1857, it is the fourth largest city in the state with a 2010 census population of 161,791 as of April 1, 2010...	0.00	– Portland, OR	Southern terminus of Segment 1
		10.99	Ridgefield NWR Ridgefield National Wildlife Refuge The Ridgefield National Wildlife Refuge Complex is a wildlife preserve, one of the National Wildlife Refuges operated by the United States Fish and Wildlife Service...	Northern terminus of Segment 1
		11.00	Physical gap
	Ridgefield Ridgefield, Washington Ridgefield is a city in the pastoral, rolling-hills countryside of northern Clark County, Washington, United States. The population was 4,763 at the 2010 census....		Main Street	Southern terminus of Segment 2
		13.97		Northern terminus of Segment 2