The 2021 GMC Acadia is available as a 4-door, 7-seat sport utility. Starting at $29,800, the 2021 GMC Acadia SL FWD is powered by a 2.5LL , 4 -cylinder engine mated to an automatic transmission that returns an EPA estimated 21-mpg in the city and 27-mpg on the highway. The top of the line 2021GMCAcadiaDenali AWD , priced at $ 48,600 , is powered by a 3.6LL , 6 - cylinder engine mated to an automatic transmission that returns an EPA estimated 19-mpg in the city and 26-mpg on the highway.