The Marcus Amphitheater is an amphitheater on the south end of the Henry Maier Festival Park (also known locally as the Summerfest grounds) in Milwaukee, Wisconsin. The amphitheater was built after an extremely overcrowded concert in 1984 to carry crowds of 25,000 fans during concerts. It was completed in 1987, with the principal contribution from the Marcus Corporation.
The amphitheater plays host to a variety of concerts and events during the spring, summer and fall.
It is also the venue for headlining acts performing at Summerfest.