Wikipedia:WikiProject U.S. Roads/Washington/Highways of Statewide Significance

The following are Highways of Statewide Significance or in the National Highway System:
 * US 2: I-5 to Idaho
 * SR 3: US 101 to SR 104
 * SR 4: US 101 to SR 432
 * NHS only: SR 432 to I-5
 * I-5: Oregon to Canada
 * SR 8: US 12 to US 101
 * SR 9: SR 522 to SR 530 (HSS only), SR 546 to British Columbia (both)
 * NHS only SR 11: ferry to I-5
 * US 12: US 101 to Idaho
 * SR 14: I-5 to US 97
 * SR 16: SR 3 to I-5
 * SR 17: US 395 to Moses Lake Airport (HSS only north of I-90)
 * SR 18: SR 99 to I-90
 * SR 19: SR 104 to SR 20 (HSS only)
 * SR 20: US 101 to US 2 (HSS only east of I-5)
 * SR 20 Spur: ferry to SR 20
 * SR 22: I-82 to US 97
 * SR 26: I-90 to US 195
 * SR 28: US 2 to SR 281
 * I-82: I-90 to Oregon
 * I-90: I-5 to Idaho
 * NHS only SR 96: park and ride to I-5
 * US 97: Oregon to Canada (HSS only between SR 22 and I-82)
 * SR 99: I-5 to proposed SR 509 (HSS only), SR 509 to SR 104 (both)
 * NHS only: South 188th Street to airport
 * US 101: Oregon to SR 401, SR 4 to I-5
 * SR 104: US 101 to I-5
 * NHS only SR 109: US 101 to Pacific Beach
 * SR 125: Oregon to US 12
 * SR 127: US 12 to SR 26
 * NHS only SR 128: US 12 to Idaho
 * NHS only SR 166: SR 16 to naval fuel depot
 * SR 167: I-5 to I-405
 * SR 169: SR 164 to I-405 (HSS only)
 * I-182: I-82 to US 395
 * US 195: Idaho to I-90
 * I-205: Oregon to I-5
 * SR 240: Stevens Drive to US 395 (HSS only east of I-182)
 * SR 270: US 195 to Idaho
 * SR 281: I-90 to SR 28
 * NHS only SR 303: SR 304 to SR 3
 * SR 304: SR 3 to ferry
 * SR 305: ferry to SR 3
 * SR 307: SR 305 to SR 104
 * SR 310: SR 3 to SR 304
 * US 395: I-82 to Canada
 * SR 401: US 101 to SR 4
 * I-405: I-5 to I-5
 * SR 432: SR 4 to I-5
 * SR 433: Oregon to SR 432
 * NHS only SR 500: I-5 to SR 503
 * SR 501: I-5 to Port of Vancouver
 * NHS only SR 502: I-5 to SR 503
 * NHS only SR 503: SR 500 to SR 502
 * SR 509: I-705 to 11th Street (HSS only north of Marine View Drive), I-5 (HSS as proposed; NHS via South 188th Street) to SR 99
 * SR 512: I-5 to SR 167
 * NHS only SR 513: SR 520 to Northeast 73rd Street
 * NHS only SR 516: I-5 to SR 167
 * SR 518: SR 509 to I-5
 * SR 519: I-90 to ferry
 * NHS only to West Seattle Bridge (via Alaskan Way)
 * SR 520: I-5 to SR 202
 * SR 522: I-5 to US 2
 * NHS only SR 524: park and ride to I-5
 * SR 525: I-5 to SR 20
 * SR 526: SR 525 to I-5
 * SR 529: I-5 to Port of Everett
 * SR 530: I-5 to SR 9 (HSS only)
 * SR 539: I-5 to Canada
 * SR 543: I-5 to Canada
 * SR 546: SR 539 to SR 9
 * SR 704: I-5 to SR 7 (HSS only)
 * I-705: I-5 to Schuster Parkway
 * SR 970: I-90 to US 97

Selected non-state highway NHS routes:
 * 11th Street: I-705 to SR 509
 * Airport Road: I-5 to SR 526
 * Airport Way/Logan Avenue/North 6th Street/Park Avenue/Park Drive: SR 167 to I-405
 * Denny Way: Western Avenue to I-5
 * Western Avenue/Elliott Avenue/15th Avenue Northwest/Holman Road/Greenwood Avenue/Westminster Way: SR 99 to SR 99
 * East Marginal Way: I-5 (via Boeing Access Road) to SR 99
 * West Marginal Way: SR 509 to West Seattle Bridge
 * West Seattle Bridge: West Marginal Way to I-5