Washington State Route 530

State Route 530
Oso Slide Memorial Highway
SR 530 highlighted in red
Route information
Auxiliary route of I-5
Maintained by WSDOT
Length	50.45 mi[1] (81.19 km)
Existed	1964–present
Major junctions
West end	I-5 in Arlington
Major intersections	SR 9 in Arlington
East end	SR 20 in Rockport
Location
Country	United States
State	Washington
Counties	Snohomish, Skagit
Highway system
State highways in Washington Interstate US State Scenic Pre-1964 1964 renumbering Former
← SR 529 → SR 531

State Route 530 (SR 530) is a state highway in western Washington, United States. It serves Snohomish and Skagit counties, traveling 50.52 miles (81.30 km) from an interchange with Interstate 5 (I-5) southwest of Arlington past SR 9 in Arlington and Darrington to end at SR 20 in Rockport. Serving the communities of Arlington, Arlington Heights, Oso, Darrington and Rockport, the roadway travels parallel to a fork of the Stillaguamish River from Arlington to Darrington, the Sauk River from Darrington to Rockport and the Whitehorse Trail from Arlington to Darrington.

The first segment of SR 530 to appear on a map was a road extending from Arlington to Oso in 1899. The first segment to be state-maintained was Secondary State Highway 1E (SSH 1E), which ran from Conway to Arlington. SSH 1E was extended to Darrington in 1957 and later renumbered to SR 530 in 1964; the road was extended to Rockport in 1983 and later the route from Conway to I-5 was removed from the system in 1991. A section of the highway was destroyed in the 2014 Oso landslide and was rebuilt; a longer portion of SR 530 was designated the Oso Slide Memorial Highway in 2019.