Auto Club Speedway, Motorsport racing track in Fontana, California, US.

Auto Club Speedway is a motorsport racing track in Fontana, California, featuring an oval course roughly 3.2 kilometers (2 miles) around with wide straights between the turns. The facility includes multiple grandstand sections, hospitality areas, and pit lanes that give spectators views of the ongoing preparations.

Roger Penske and Kaiser Steel announced the track on April 20, 1994, on the site of the abandoned Kaiser Steel Mill in Fontana; construction began November 22, 1995, and the speedway opened in 1997. The mill's 100-foot water tower was kept inside the oval as a scoreboard. NASCAR ran races annually from 1997 until 2023, when the track closed for reconstruction and demolition began in October 2023.

The track's name changed from California Speedway to Auto Club Speedway in 2008 under a naming-rights deal with the Automobile Club of Southern California, which ended in March 2023. The 100-foot water tower of the former Kaiser Steel Mill was kept in the infield and used as a scoreboard. The 2006 Discover IE FanZone behind the main grandstand added a Wolfgang Puck restaurant, shade areas and an entertainment stage.

The track closed in 2023 and demolition began in October 2023, so there is no race-day visiting; the site sits in unincorporated San Bernardino County near Fontana, 47 mi (76 km) east of Los Angeles. It was served by Interstates 10 and 15 and by a Metrolink station behind the backstretch.

The 100-foot water tower of the former Kaiser Steel Mill was kept standing inside the infield and reused as a scoreboard. The site also held a quarter-mile dragstrip, the Auto Club Dragway, built outside the backstretch in 2001. Gil de Ferran set the practice lap record in 2000 at 241.428 mph (388.5 km/h).