Aftershock Festival is one of the largest rock and metal festivals on the West Coast of the United States. Held annually at Discovery Park in Sacramento, the event has grown from a single-day hard rock gathering into a massive four-day destination festival that attracts fans from across the country.

The festival was founded in 2012 by promoter Danny Wimmer Presents. The inaugural event was a one-day show headlined by bands such as Stone Temple Pilots and Deftones. Due to strong attendance and demand, Aftershock expanded to two days in 2013, eventually growing to three days and, by 2022, to a four-day format. Its expansion reflects both the enduring popularity of heavy music and Sacramento’s growing status as a festival destination.

Today, Aftershock routinely draws around 150,000 to 160,000 total attendees across the four days, with tens of thousands of fans filling Discovery Park each day. The festival has become known not only for its stacked lineups but also for its large-scale production, multiple stages, art installations, food vendors, and immersive fan experiences. Its riverside setting at the confluence of the Sacramento and American Rivers gives it a distinctive atmosphere compared to many urban festivals.

Musically, Aftershock focuses primarily on rock and metal but spans a wide spectrum of subgenres. Hard rock, alternative rock, heavy metal, metalcore, punk rock, post-hardcore, industrial, nu-metal, and even hip-hop with heavy crossover appeal have all had a place on its stages. Over the years, major acts such as Metallica, Guns N’ Roses, Tool, My Chemical Romance, and Slipknot have headlined. At the same time, the festival consistently showcases rising bands and underground artists, making it both a celebration of legacy acts and a platform for new talent.

Aftershock’s blend of established icons, genre diversity, and high-energy crowds has helped it become a cornerstone event in the American rock festival circuit. More than a decade after its debut, it continues to evolve while staying rooted in its core identity: loud, heavy, and unapologetically rock-driven.