Festival dijadwalkan dari 01 Sep hingga 18 Sep 2021 (17 hari).
Summerfest berlangsung di Milwaukee, United States. Berikut adalah alamat lengkap festival: Henry Maier Festival Park; Milwaukee, Wisconsin, United States
Green Day, Chris Stapleton, Jonas Brothers, twenty one pilots, Zac Brown Band, Fall Out Boy, Dropkick Murphys, Luke Bryan, Weezer, Falling in Reverse, Mother Mother, Miley Cyrus, Styx, Rise Against, Wiz Khalifa, Lindsey Stirling, ZZ Top, REO Speedwagon, Nelly, Dave Matthews Band, Blackberry Smoke, SpiritBox, 311, Ani DiFranco, Polo G.
Genre dan sub-genre yang paling populer dari edisi sebelumnya adalah:
rock
pop
hip hop
alternative
alternative rock
indie
hard rock
indie rock
pop rock
classic rock
rnb
indie pop
emo
metal
punk rock
acoustic
blues rock
grunge
new wave