Mill Creek is a 26-mile (42 km) tributary of the Willamette River that drains a 111-square-mile (290 km2) area of Marion County in the U.S. state of Oregon.

[4] Flowing generally west from its source south of Silver Falls State Park, it passes through the cities of Aumsville, Stayton, Sublimity, and Turner before emptying into the Willamette in Salem.

At Turner, Franzen Reservoir is to the right, and Perrin Lateral enters from the left; like Salem Ditch, it is an artificial channel that carries water from the North Santiam River to Mill Creek.

Along the I-5 stretch, Walter Wirth Lake and McNary Field (Salem Municipal Airport) are on the left; near Route 22, the unincorporated neighborhood of Four Corners is on the right.

[6] Another diversion canal, Shelton Ditch, built in the mid-1800s, runs from Mill Creek near the municipal airport through the southern edge of downtown Salem.

[6] In January 2012, heavy rain from a winter storm caused many Oregon streams, including Mill Creek, to overflow their banks.