Sheridan is a city in Yamhill County, Oregon, United States. Platted in the 1860s when it received a post office, the city was incorporated in 1880. A major fire burned much of the city in 1913, and a flood covered much of the city in 1964. The population of the city as of the 2010 Census was 6,127, an increase from 3,570 at the 2000 census. However, the 2000 Census count failed to include those incarcerated at the federal prison in the city, while the newer count did include those inmates.Located in the western part of the Willamette Valley, the city is at the base of the Northern Oregon Coast Range along the South Yamhill River. Sheridan lies west of the county seat of McMinnville, along Oregon Route 18. This highway and Oregon Route 18 Business run east–west through Sheridan and nearby Willamina, parallel to the river. Sheridan Bridge is the only river crossing within Sheridan.