Racing at what would become PIR began in 1961, when competitors raced on the paved streets left over from Vanport, a city destroyed in a 1948 flood. Early racing was considered dangerous, as cars leaving the circuit could collide with concrete foundations or fall into ponds. The track was properly paved during the 1970s after sanctioning bodies threatened to withdraw due to deteriorating conditions.
Open-wheel racing came to Portland in 1984 when PPG IndyCar World Series cars arrived, with Al Unser Jr. claiming the first victory. Through the 1980s and 1990s, Portland became one of the signature road-course venues on the CART calendar, producing some of the closest finishes in Indy car history. In 1986, Michael Andretti lost fuel pressure approaching the final turn on the last lap, allowing his father Mario to catch and beat him by 0.070 seconds — at the time the closest finish in Indy car history. A three-wide finish in 1997 saw Mark Blundell edge Gil de Ferran by 0.027 seconds, the closest three-car finish in CART series history.
After an eleven-year hiatus, IndyCar racing returned to Portland in September 2018. The circuit underwent a major renovation at the end of the 2007 season and beginning of 2008, with new asphalt, widened turns four through seven, a sharpened turn seven, and Formula One-style curbing installed.
The modern Grand Prix circuit runs clockwise and measures 1.967 miles (3.166 km), incorporating twelve turns including a hard chicane at the end of the front straight known as the Shelton Chicane, named in honor of Vanport racing legend Monte Shelton. Without the chicane, the circuit reverts to a nine-turn, 1.915-mile (3.082 km) configuration. The circuit is noted for being almost perfectly flat.
In December 2022, it was announced that Formula E would race at PIR beginning in the 2022–23 season, replacing the Brooklyn Street Circuit on the calendar. The circuit used a slightly modified layout to suit Formula E's needs. Nick Cassidy won the inaugural Portland ePrix in June 2023, and António Félix da Costa won both races held in June 2024. The Formula E rounds added a new international racing dimension to a circuit that had previously been best known for IndyCar and CART events.
PIR's winners list includes some of the most accomplished open-wheel drivers: Mario Andretti (1985–1986), Emerson Fittipaldi (1989), Michael Andretti (1990–1992), Bobby Rahal (1987), Sébastien Bourdais (2004, 2007), Will Power (2019, 2024), and Álex Palou (2021, 2023). Will Power set the qualifying record of 0:57.3467 seconds during the 2018 Grand Prix of Portland.
Portland International Raceway represents a rare example of a publicly owned motorsport facility — it is operated by the City of Portland — that has remained on international racing calendars for decades. Its urban setting near residential neighborhoods has drawn ongoing scrutiny regarding the use of leaded gasoline during certain race events, with the City actively pursuing a carbon-neutral status for the venue. The arrival of Formula E underscored the circuit's adaptability and its continued relevance in the evolving landscape of top-level motorsport.