The Tri-County Metropolitan Transportation District of Oregon, branded as TriMet, is a transit agency that serves most of the Oregon part of the Portland metropolitan area. Created in 1969 by the Oregon legislature, the district replaced five private bus companies that operated in the three counties: Multnomah, Washington, and Clackamas. TriMet began operating a light rail system, MAX, in 1986, which has since been expanded to five lines that now cover 59.7 miles (96.1Â km). It also operates the WES Commuter Rail line since 2009. It also provides the operators and maintenance personnel for the city of Portland-owned Portland Streetcar system. In 2024, the system had a ridership of 66,876,200, or about 202,800 per weekday as of the third quarter of 2025.
In addition to rail lines, TriMet provides the region's bus system, as well as LIFT paratransit service. There are over 650 buses on 79 lines as of September 2025. In 2018, the entire system averaged 310,000 rides per weekday and operates buses and trains between the hours of approximately 5Â a.m. and 2Â a.m. TriMet's annual budget for FY 2018 is $525.8Â million, with 30% of resources coming from a district-wide payroll tax and 10% from fares. The district is overseen by a seven-person board of directors appointed by the state's governor. As of 2022, the agency has around 3,428 employees.