The 1991 Champion Spark Plug 500 was the 13th stock car race of the 1991 NASCAR Winston Cup Series season and the tenth iteration of the event. The race was held on Sunday, June 16, 1991, in Long Pond, Pennsylvania, at Pocono Raceway, a 2.5 miles (4.0 km) triangular permanent course. The race took the scheduled 200 laps to complete. In the final laps of the race, owner-driver Darrell Waltrip would mount a late-race charge for the lead, passing with 18 laps to go in the race to take his 81st career NASCAR Winston Cup Series victory and his second and final victory of the season.^[1][2][3] To fill out the top three, Richard Childress Racing driver Dale Earnhardt and Roush Racing driver Mark Martin would finish second and third, respectively.

The race was held at Pocono International Raceway, which is a three-turn superspeedway located in Long Pond, Pennsylvania. The track hosts two annual NASCAR Sprint Cup Series races, as well as one Xfinity Series and Camping World Truck Series event. Until 2019, the track also hosted an IndyCar Series race.

Pocono International Raceway is one of a very few NASCAR tracks not owned by either Speedway Motorsports, Inc. or International Speedway Corporation. It is operated by the Igdalsky siblings Brandon, Nicholas, and sister Ashley, and cousins Joseph IV and Chase Mattioli, all of whom are third-generation members of the family-owned Mattco Inc, started by Joseph II and Rose Mattioli.

Outside of the NASCAR races, the track is used throughout the year by the Sports Car Club of America (SCCA) and motorcycle clubs as well as racing schools and an IndyCar race. The triangular oval also has three separate infield sections of racetrack – North Course, East Course and South Course. Each of these infield sections use a separate portion of the tri-oval to complete the track. During regular non-race weekends, multiple clubs can use the track by running on different infield sections. Also some of the infield sections can be run in either direction, or multiple infield sections can be put together – such as running the North Course and the South Course and using the tri-oval to connect the two.

Qualifying was split into two rounds. The first round was held on Friday, June 14, at 3:00 PM EST. Each driver would have one lap to set a time. During the first round, the top 15 drivers in the round would be guaranteed a starting spot in the race. If a driver was not able to guarantee a spot in the first round, they had the option to scrub their time from the first round and try and run a faster lap time in a second round qualifying run, held on Saturday, June 15, at 10:30 AM EST. As with the first round, each driver would have one lap to set a time. For this specific race, positions 16-40 would be decided on time,^[4] and depending on who needed it, a select amount of positions were given to cars who had not otherwise qualified but were high enough in owner's points; up to two provisionals were given. If needed, a past champion who did not qualify on either time or provisionals could use a champion's provisional, adding one more spot to the field.

Mark Martin, driving for Roush Racing, would win the pole, setting a time of 55.557 and an average speed of 161.996 miles per hour (260.707 km/h) in the first round.^[5]

No drivers would fail to qualify.