U.S Numbered Highways
Highways originally had names rather than numbers. In 1918 Wisconsin was the first state to post state route numbers.Michigan followed soon after. By the 1920s, several states were posting state route numbers. In the early 1920s, New York and the New England states developed a regional highway numbering system. The American Association of State Highway Officials (AASHO) and the US Bureau of Public Roads conducted a series of meetings beginning in spring of 1925 to devise a national numbering system to aid interstate travelers. This system was intended to replace the disorganized system of named national auto trails created by several private organizations. The draft numbering plan was ready by fall 1925. The basic rules were set up with odd-numbered routes running north to south and even east to west. The numbers progressed fro the northeast corner of the United States. Thus US 1 is on the East Coast, US 99 and US 101 in the west. One and two-digit numbers were used for the longer or more important routes with three digit numbers used for shorter or less important routes. US 101 is an exception being equal in importance to a two digit route. Most of the numbers in the draft plan with a few exceptions were used in the final plan. The 1926 Rand McNally Road Atlas used the numbers from the draft plan. The final plan was approved in November 1926 and route marker signs began to be posted.
Here are links to US numbered highways in Washington State
Individual US Routes:
US 10 (decomissioned) US 410 (decommissioned)
Branches of US 30: US 730 US 830 (decommissioned)
US 95 (realigned, no longer in Washington State) US 195 US 295 (decommissioned) US 395
US 97 US 197
US 99 (decommissioned)
R. V. Droz had a site that no longer exists that had a comprehensive listing and history of all US numbered routes.
Primary State Hwys Secondary State Hwys