Portland () is the largest city in the U.S. state of Oregon and the seat of Multnomah County. It is a major port in the Willamette Valley region of the Pacific Northwest, at the confluence of the Willamette and Columbia rivers. The city covers 145 square miles (380 square kilometers) and had an estimated population of 639,863 in 2016, making it the 26th most populous city in the United States, and the second-most populous in the Pacific Northwest. Approximately 2,424,955 people live in the Portland metropolitan statistical area (MSA), making it the 25th most populous MSA in the United States. Its Combined Statistical Area (CSA) ranks 18th with a population of 3,160,488. Roughly 60% of Oregon's population resides within the Portland metropolitan area.

Named after Portland, Maine, which in turn was named after the Isle of Portland in Dorset, the Oregon settlement began to be populated in the 1830s 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 19th 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, Portland became noted for its growing 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. The city government is notable for its land-use planning and investment in public transportation. Portland is frequently recognized as one of the world's most environmentally conscious cities because of its high walkability, large community of bicyclists, farm-to-table dining, expansive network of public transportation options, and over 10,000 acres (4,000 hectares) of public parks. 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. "Keep Portland Weird" is an unofficial slogan for the city.