The Washington State Route system is the official name given to the highway system in Washington owned, maintained, and managed by the Washington State Department of Transportation. Every highway route in Washington State is considered a state route (SR), regardless of designation.

Former system

From 1923 until 1965, Washington had two different levels of highways, differentiated by use of numbers and letters. Primary State Highways (PSH) were assigned a one or two digit number. Secondary State Highways (SSH) were either spur or loop routes, designated by a letter suffix (i.e. SSH 1-D split from PSH 1). By the 1960s this system was becoming confusing, especially as Interstate Highway System was taking over routes. It was then decided to reformulate the system.

Current system

The current system was adopted on December 1, 1965.[1] Major routes get one or two digit numbers, or are U.S. Highways. Odd-numbered major routes run north-south and are numbered from 3 in the west to 31 in the east. Even-numbered routes are similar, but run in three strips (separated by I-5 and roughly the Columbia River). The west strip runs from 4 north to 8. 14 picks up east of I-5, running north to 20, and 22 to 28 run through the third strip.

Some exceptions are present due to U.S. Highways and former U.S. Highways; for example SR 10 is former US 10 and SR 410 is former US 410 .

Three-digit numbers are assigned to minor routes. They are typically assigned a "parent" one or two digit route, and a number is added to the end. For instance, 104 and 117 are spurs of US 101, 505 and 527 are spurs of I-5, and 261 is a spur of 26. Several U.S. Highways are assigned two-digit numbers (which fit the grid) - US 97 is 15 and US 395 is 29. US 97 has spurs using both methods (examples are 153 and 971) and US 395 has spurs like 291 and 397. Typically the three-digit routes run in sequence from the south or west end of the parent to the north or east end.

"Children" of 9 are only two digits (92 and 96); otherwise they would conflict with children of I-90.

List of routes

• U.S. Highway 101
  • Washington State Route 100
  • Washington State Route 101
  • Washington State Route 102
  • Washington State Route 103
  • Washington State Route 104
  • Washington State Route 105
  • Washington State Route 106
  • Washington State Route 107
  • Washington State Route 108
  • Washington State Route 109
  • Washington State Route 110
  • Washington State Route 111
  • Washington State Route 112
  • Washington State Route 113
  • Washington State Route 115
  • Washington State Route 116
  • Washington State Route 117
  • Washington State Route 118
  • Washington State Route 119
• U.S. Highway 2
  • Washington State Route 202
  • Washington State Route 203
  • Washington State Route 204
  • Washington State Route 206
  • Washington State Route 207
• Washington State Route 3
  • Washington State Route 300
  • Washington State Route 302
  • Washington State Route 303
  • Washington State Route 304
  • Washington State Route 305
  • Washington State Route 307
  • Washington State Route 308
  • Washington State Route 310
  • Washington State Route 339
• Washington State Route 4
  • Washington State Route 401
  • Washington State Route 409
  • Washington State Route 410 (former U.S. Highway 410, not actually connected to SR 4)
  • Washington State Route 411 (child of SR 410)
  • Washington State Route 432
  • Washington State Route 433
• Interstate 5
  • Interstate 205
  • Interstate 405
  • Interstate 705
  • Washington State Route 500
  • Washington State Route 501
  • Washington State Route 502
  • Washington State Route 503
  • Washington State Route 504
  • Washington State Route 505
  • Washington State Route 506
  • Washington State Route 507
  • Washington State Route 508
  • Washington State Route 509
  • Washington State Route 510
  • Washington State Route 512
  • Washington State Route 513
  • Washington State Route 515
  • Washington State Route 516
  • Washington State Route 518
  • Washington State Route 519
  • Washington State Route 520
  • Washington State Route 522
  • Washington State Route 523
  • Washington State Route 524
  • Washington State Route 525
  • Washington State Route 526
  • Washington State Route 527
  • Washington State Route 528
  • Washington State Route 529
  • Washington State Route 530
  • Washington State Route 531
  • Washington State Route 532
  • Washington State Route 534
  • Washington State Route 536
  • Washington State Route 538
  • Washington State Route 539
  • Washington State Route 542
  • Washington State Route 543
  • Washington State Route 544
  • Washington State Route 546
  • Washington State Route 547
  • Washington State Route 548
  • Washington State Route 599 (runs between I-5 and SR 99)
• Washington State Route 6
• Washington State Route 7
  • Washington State Route 702
  • Washington State Route 706
• Washington State Route 8
• Washington State Route 9
  • Washington State Route 92
  • Washington State Route 96
• Washington State Route 10 (former U.S. Highway 10)
• Washington State Route 11
• U.S. Highway 12
  • Washington State Route 121
  • Washington State Route 122
  • Washington State Route 123
  • Washington State Route 124
  • Washington State Route 125
  • Washington State Route 126
  • Washington State Route 127
  • Washington State Route 128
  • Washington State Route 129
  • Washington State Route 131
• Washington State Route 14
  • Washington State Route 141
  • Washington State Route 142
• Washington State Route 15 (US 97)
  • Washington State Route 150
  • Washington State Route 153
  • Washington State Route 155
• Washington State Route 16
  • Washington State Route 160
  • Washington State Route 161
  • Washington State Route 162
  • Washington State Route 163
  • Washington State Route 164
  • Washington State Route 165
  • Washington State Route 166
  • Washington State Route 167
  • Washington State Route 169
• Washington State Route 17
  • Washington State Route 170
  • Washington State Route 171
  • Washington State Route 172
  • Washington State Route 173
  • Washington State Route 174
  • Washington State Route 175
• Washington State Route 18
  • Washington State Route 181
• Washington State Route 19
• U.S. Highway 195
  • Washington State Route 193
  • Washington State Route 194
• Washington State Route 20
  • Washington State Route 211
  • Washington State Route 215
• Washington State Route 21
• Washington State Route 22
  • Washington State Route 221
  • Washington State Route 223
  • Washington State Route 224
  • Washington State Route 225
• Washington State Route 23
  • Washington State Route 231
• Washington State Route 24
  • Washington State Route 240
  • Washington State Route 241
  • Washington State Route 243
• Washington State Route 25
• Washington State Route 26
  • Washington State Route 260
  • Washington State Route 261
  • Washington State Route 262
  • Washington State Route 263
• Washington State Route 27
  • Washington State Route 270
  • Washington State Route 271
  • Washington State Route 272
  • Washington State Route 274
  • Washington State Route 278
• Washington State Route 28
  • Washington State Route 281
  • Washington State Route 282
  • Washington State Route 283
  • Washington State Route 285
• Washington State Route 29 (US 395)
  • Washington State Route 290
  • Washington State Route 291
  • Washington State Route 292
• Washington State Route 31
• U.S. Highway 395
  • Washington State Route 397
• Washington State Route 41
• Interstate 82
  • Interstate 182
  • Washington State Route 821
  • Washington State Route 823
• Interstate 90
  • Washington State Route 900
  • Washington State Route 902
  • Washington State Route 903
  • Washington State Route 904
  • Washington State Route 906
  • Washington State Route 908
• U.S. Highway 97
  • Washington State Route 970
  • Washington State Route 971
• Washington State Route 99
• U.S. Highway 197
• Washington State Route 410
• U.S. Highway 730

See also

• List of state highways in the United States

External links

• Washington State Department of Transportation
• Highways of Washington State