Interstate 205 (I-205) is an auxiliary Interstate Highway in the Portland metropolitan area of Oregon and Washington, United States. The north–south freeway serves as a bypass route of I-5 along the east side of Portland, Oregon, and Vancouver, Washington. It intersects several major highways and serves Portland International Airport.

The Portland metropolitan area is a metro area with its core in the U.S. states of Oregon and Washington. It has 5 principal cities the largest being Portland, Oregon. The U.S. Office of Management and Budget (OMB) identifies it as the Portland–Vancouver–Hillsboro, OR–WA Metropolitan Statistical Area, a metropolitan statistical area used by the United States Census Bureau (USCB) and other entities. The OMB defines the area as comprising Clackamas, Columbia, Multnomah, Washington, and Yamhill Counties in Oregon, and Clark and Skamania Counties in Washington. The area had a population of 2,512,859 at the 2020 census, an increase of over 12% since 2010.