The Milwaukie branch is a railway line in Clackamas County, Oregon, in the United States.

It was originally built in 1910 by the Beaverton and Willsburg Railroad, a subsidiary of the Southern Pacific Transportation Company.

[1][2] The Milwaukie branch passes Elk Rock Island and follows the Willamette River before crossing it, using the Lake Oswego Railroad Bridge.

On the west bank of the Willamette the line travels a short distance before connecting with the Newberg branch in Lake Oswego, Oregon.

[7] The Portland and Western Railroad groups the line with part of the Newberg branch as the Willsburg District.