State Route 526 (SR 526), also known as the Boeing Freeway, is a state highway in Snohomish County, Washington, United States. The east–west highway travels and connects SR 525 in Mukilteo to Interstate 5 (I-5) in southern Everett. The highway serves the Boeing Everett Factory and Paine Field; it also serves as a main route to the city of Mukilteo and the state-run ferry to Whidbey Island. SR 526 was established during the 1964 state highway renumbering as the successor to Secondary State Highway 1I (SSH 1I) between Mukilteo and Everett. Its original route followed a wagon road traveling along Possession Sound that opened in 1914; it was moved onto its current route in 1967 after Boeing announced its intention to build a factory in Everett for its 747 airliner. Route description SR 526 begins as 84th Street Southwest at a signalized intersection with SR 525, named the Mukilteo Speedway, at Nelsons Corner in Mukilteo. The highway travels east through a residential neighborhood, heading towards an intersection with Paine Field Boulevard, signed as SR 525 Spur, at the Future of Flight Aviation Center and Paine Field. SR 526 turns northeast as the four-lane continuation of Paine Field Boulevard, curving north around the north–south runway of Paine Field and south of Japanese Gulch, into the city of Everett. The highway becomes the controlled-access Boeing Freeway and passes under the Boeing Access Road, a taxiway that connects the Boeing Everett Factory to Paine Field. SR 526 continues east and intersects Airport Road in a diamond interchange and Seaway Boulevard in a semi-directional T interchange, the main access roads to Paine Field and the Boeing factory, respectively, before widening to six lanes as it approaches its eastern terminus, an interchange with I-5. The freeway travels through a diamond interchange with Evergreen Way, located east of a pedestrian bridge over SR 526 and south of Cascade High School, where traffic heading towards I-5 northbound on a left directional exit and traffic heading towards I-5 southbound splits into two lanes, a normal lane and a high-occupancy vehicle lane (HOV lane). SR 526 continues east, briefly paralleling the Interurban Trail, before the freeway travels towards I-5 on flyover ramps and the highway terminates at the northern terminus of SR 99 and the northern terminus of SR 527. Every year, the Washington State Department of Transportation (WSDOT) conducts a series of surveys on its highways in the