Thomas Creek is a stream, about 35 miles (56 km) long, in Linn County in the U.S. state of Oregon. Beginning in Willamette National Forest on the western slopes of the Cascade Range, the creek flows generally west through Santiam State Forest and farmland to meet the South Santiam River west of Scio. The creek at times has flooded Scio, particularly in 1964. The drop in elevation on its upper reaches, coupled with its flow volume, make it suitable at times for whitewater canoes and kayaks. The stream supports populations of smallmouth bass, cutthroat trout, and other fish.