The 2023 The Loop 121 was the 16th stock car race of the 2023 NASCAR Xfinity Series, and the inaugural iteration of the event. The race was scheduled to be held on Saturday, July 1, 2023, but after 25 laps, the race was postponed until Sunday, July 2, due to inclement weather. The race was held in Chicago, Illinois at the Chicago Street Course, a 2.2 miles (3.5 km) street course. The race was originally scheduled to be contested over 55 laps, but was decreased to 25 laps (2 laps short of the typical point where the race could be called official) due to downpouring rain and standing water. Cole Custer, driving for Stewart-Haas Racing, would lead all 25 laps of the race after starting from the pole, and earned his 12th career NASCAR Xfinity Series win, and his second of the season.^[1] To fill out the podium, John Hunter Nemechek, driving for Joe Gibbs Racing, and Justin Allgaier, driving for JR Motorsports, would finish 2nd and 3rd, respectively. This was the first street race to be contested in the series.^[2]

The Chicago Street Course is a 2.2 mi (3.5 km) street circuit located in the city of Chicago, Illinois, United States. It hosts the NASCAR Cup Series and NASCAR Xfinity Series. The track was initially a conceptual track on iRacing made for the eNASCAR iRacing Pro Invitational Series in 2021.

The track for the actual race in 2023 ended up being the exact same layout as the version used in 2021 for the eNASCAR iRacing Pro Invitational Series. The start/finish line is located on South Columbus Drive in front of Buckingham Fountain in Grant Park. The cars will go south and then turn left onto East Balbo Drive and then right onto South Lake Shore Drive (also part of U.S. Route 41), which is alongside Lake Michigan. The cars will then turn right onto East Roosevelt Road and then make another right, which gets them back onto South Columbus Drive where they are going north. They will then reach the intersection of South Columbus Drive and East Balbo Drive again and will make a left turn. When they are back on East Balbo Drive, they will cross a bridge over the Metra Electric District tracks. Next, the cars will turn right onto South Michigan Avenue and go north, go onto East Congress Plaza Drive and back onto South Michigan Ave. Lastly, they will make a right turn onto East Jackson Drive, go back across the Metra Electric tracks, and right back onto South Columbus Drive to the start/finish line.^[2]

The first and only practice session was held on Saturday, July 1, at 10:00 AM CST, and would last for 50 minutes.^[3] Justin Marks, driving for Kaulig Racing, would set the fastest time in the session, with a lap of 1:32.138, and an average speed of 85.958 mph (138.336 km/h).^[4]

Qualifying was held on Saturday, July 1, at 11:00 AM CST.^[3] Since the Chicago Street Course is a street course, the qualifying system is a two group system, with two rounds. Drivers will be separated into two groups, Group A and Group B. Each driver will have multiple laps to set a time. The fastest 5 drivers from each group will advance to the final round. The fastest driver to set a time in that round will win the pole.^[5] Cole Custer, driving for Stewart-Haas Racing, would score the pole for the race, with a lap of 1:30.421, and an average speed of 87.590 mph (140.962 km/h).^[6]

Only 25 laps of the race were run, the entirety of stage 1 and the first 10 laps of stage 2. After several lightning delays on Saturday, NASCAR planned to postpone the rest of the race to Sunday, the morning before the Cup race. However, torrential rain on Sunday morning (including several flash flood warnings issued for the region) led to NASCAR issuing an unprecedented decision to call the race before the point the race could be called official.

Stage 1 Laps: 15

Stage 2 Laps: 10*^{[lower-alpha 1]}

Stage 3 Laps: 0*