The 2018 South Point 400 was a Monster Energy NASCAR Cup Series race held on September 16, 2018 at Las Vegas Motor Speedway in Las Vegas. Contested over 272 laps—extended from 267 laps due to an overtime finish, on the 1.5 mi (2.4 km) asphalt intermediate speedway, it was the 27th race of the 2018 Monster Energy NASCAR Cup Series season, first race of the Playoffs, and the first race of the Round of 16.