Portland ( PORT-lənd) is a port city in the Pacific Northwest and the most populous city in the U.S. state of Oregon. Situated in the northwestern area of the state at the confluence of the Willamette and Columbia rivers, it is the county seat of Multnomah County, Oregon's most populous county. As of 2020, Portland's population was 652,503, making it the 26th-most populous city in the United States, the sixth-most populous on the West Coast, and the second-most populous in the Pacific Northwest, after Seattle. Approximately 2.5 million people live in the Portland–Vancouver–Hillsboro, OR–WA metropolitan statistical area, making it the 25th most populous in the United States. About half of Oregon's population resides within the Portland metropolitan area.

Named after Portland, Maine, which is itself named after the English Isle of Portland, the Oregon settlement began to be populated in the 1840s, near the end of the Oregon Trail. Its water access provided convenient transportation of goods, and the timber industry was a major force in the city's early economy. At the turn of the 20th century, the city had a reputation as one of the most dangerous port cities in the world, a hub for organized crime and racketeering. After the city's economy experienced an industrial boom during World War II, its hard-edged reputation began to dissipate. Beginning in the 1960s, it became noted for its growing liberal and progressive political values, earning it a reputation as a bastion of counterculture.

The city operates with a commission-based government, guided by a mayor and four commissioners, as well as Metro, the only directly elected metropolitan planning organization in the United States. Its climate is marked by warm, dry summers and cool, rainy winters. This climate is ideal for growing roses, and Portland has been called the "City of Roses" for over a century.