Oregon City is the first city in the United States incorporated west of the Rockies. It is the county seat of Clackamas County, Oregon. As of the 2000 census, the city population was 25,754; a more recent estimate has the population at 28,964.

Known in recent decades as the site of several large paper mills on the Willamette River, the city played a significant role in the early history of the Oregon Country. It was established by Dr. John McLoughlin in 1829 near the confluence of the Clackamas River with the Willamette to take advantage of the power of Willamette Falls to run a lumber mill. During the 1840s and 1850s it was the destination for those wanting to file land claims after traveling the Oregon Trail. It was the capital of the Oregon Territory from its establishment in 1848 until 1851 and rivaled Portland for early supremacy in the area. The center of the city retains part of its historic character through the preservation of houses and other buildings from the era of the city's founding.

The city's motto is "Urbs civitatis nostrae prima et mater," as seen on the City's seal. The current mayor of Oregon City is Alice Norris.