The OR 104 designation was applied to the Fort Stevens Highway in 2002 as part of Oregon's project to assign route numbers to highways that did not have route numbers.

[3] The southern terminus of OR 104 is at a junction with US 101 near south of Warrenton.

It heads due north for 6 miles (9.7 km), ending at the entrance to Fort Stevens State Park near Hammond.

485, is a 0.95-mile (1.53 km) spur route of OR 104 in Warrenton, that connects OR 104 with US 101.

[2] Media related to Oregon Route 104 at Wikimedia Commons