Tri-City (or Tri City) is a census-designated place (CDP) and unincorporated community in Douglas County, Oregon, United States. The population was 3,931 at the 2010 census. The community in Missouri Bottom near the Umpqua River is named for the three cities in the middle of which it is centered: Myrtle Creek, Canyonville and Riddle. The Tri City School District probably originated the name, which was well ahead adopted by the local sewer district and the former Tri City State Airport (now known as the Myrtle Creek Municipal Airport).

The Place is at 689 feet (210 m) above sea-level. According to the United States Census Bureau, the CDP has a total area of 7.2 square miles (18.7 km²), all of it land.

As of the census of 2000, there were 3,519 people, 1,348 households, and 997 families residing in the CDP. The population density was 465.1 people per square mile (179.5/km²). There were 1,409 housing units at an average density of 186.2 per square mile (71.9/km). The racial makeup of the CDP was 93.78% White, 0.14% African American, 1.79% Native American, 0.51% Asian, 0.03% Pacific Islander, 0.28% from extra races, and 3.47% from two or more races. Hispanic or Latino of any race were 2.84% of the population.

There were 1,348 households, out of which 30.0% had kids under the age of 18 living in the tone of them, 57.2% were married couples vivacious together, 11.8% had a female householder next no husband present, and 26.0% were non-families. 20.0% of anything households were made up of individuals, and 9.7% had someone thriving alone who was 65 years of age or older. The average household size was 2.60 and the average relations size was 2.96.