The 1991 Marlboro 500, the eleventh running of the event, was held at the Michigan International Speedway in Brooklyn, Michigan, on Sunday, August 4, 1991. Branded as the 1991 Marlboro 500 for sponsorship reasons, the race was won by Rick Mears, his final Indy Car victory. It was also Mears' only win in the Michigan 500. The event was race number 11 of 17 in the 1991 CART PPG Indy Car World Series. 42°03′58.68″N 84°14′29.18″W / 42.0663000°N 84.2414389°W
| Race details | |
|---|---|
| Race 11 of 17 in the 1991 CART season | |
 | |
| Date | August 4, 1991 |
| Official name | 1991 Marlboro 500 |
| Location | Michigan International Speedway, Brooklyn, Michigan, United States |
| Course | Permanent racing facility 2.000 mi / 3.219 km |
| Distance | 250 laps 500.000 mi / 804.672 km |
| Weather | Partly Cloudy with temperatures up to 81 °F (27 °C); wind speeds reaching up to 18 miles per hour (29 km/h)[1] |
| Pole position | |
| Driver |  Rick Mears (Team Penske) |
| Time | 225.169 mph (362.374 km/h) |
| Podium | |
| First | Rick Mears (Team Penske) |
| Second |  Arie Luyendyk (Granatelli Racing) |
| Third | Al Unser Jr. (Galles Racing) |
- ^ Weather information for the 1991 Marlboro 500 at Wunderground