Even though the number indicates that US 410 was a spur of US 10, US 410 never connected with US 10, which is the same case with US 830 and US 30, although like the latter pair, they ran parallel in close proximity.

[3] US 410 started at an intersection with US 101 in Aberdeen, Washington, the current western terminus of US 12.

In Tacoma, US 410 turned southeast and went to Sumner, through Enumclaw, and then across Chinook Pass.

[4][5] After US 410 crossed the Lewiston–Clarkston Bridge over the Snake River into Idaho, the road went east and northeast to US 95, where it ended.

[4] The successor highway ("US 12") continued east to Lolo Pass and through Montana.

[8] A second attempt, using a tunneled route under Naches Pass, was made in 1959 and also rejected.