The 2021 FireKeepers Casino 400 was a NASCAR Cup Series race held on August 22, 2021, at Michigan International Speedway in Brooklyn, Michigan. Contested over 200 laps on the D-shaped oval, it was the 25th race of the 2021 NASCAR Cup Series season.
The race was held at Michigan International Speedway, a moderate-banked D-shaped speedway located in Brooklyn, Michigan. The track is used primarily for NASCAR events. It is known as a "sister track" to Texas World Speedway as MIS's oval design was a direct basis of TWS, with moderate modifications to the banking in the corners, and was used as the basis of Auto Club Speedway. The track is owned by International Speedway Corporation. Michigan International Speedway is recognized as one of motorsports' premier facilities because of its wide racing surface and high banking (by open-wheel standards; the 18-degree banking is modest by stock car standards).
Josh Berry replaced Corey LaJoie for the race due to COVID-19 protocols; LaJoie, then unvaccinated, had been close to a person testing positive for the COVID-19 from his Stacking Pennies podcast a week prior.
Kyle Larson was awarded the pole for the race as determined by competition-based formula.
Stage One Laps: 60
Stage Two Laps: 60
Stage Three Laps: 80
NBC Sports covered the race on the television side. Rick Allen, Jeff Burton, Steve Letarte and two-time Michigan winner, Dale Earnhardt Jr. called the race from the broadcast booth. Dave Burns, Parker Kligerman and Marty Snider handled the pit road duties from pit lane.
Radio coverage of the race was broadcast by Motor Racing Network (MRN) and simulcast on Sirius XM NASCAR Radio. Alex Hayden and Jeff Striegle called the race in the booth while the field was racing on the front stretch. Dave Moody called the race from a billboard outside of turn 2 when the field is racing through turns 1 and 2. Kyle Rickey called the race from a platform outside of turn 3 when the field races through turns 3 and 4. Steve Post and Kim Coon worked pit road for the radio side.