Leftover Salmon Detail Arch Deluxe, Two-Day St. Louis Block Party with Mountain Grass Unit, Horseshoes & Hand Grenades and OthersPhoto: Tobin VoggesserLeftover Salmon have announced Arch Deluxe, a two-day music-focused block party in St. Louis’ Gateway to the West. According to the band’s social media announcement, the block party will take place in the heart of the city. The group’s St. Louis event will arrive after their fourth annual High Country Kaua’i event on April 17-19, 2026, at the Porter Pavilion at Anaina Hou Community Park in Kilauea, Hawaii. The island occasion will include three nights of Leftover Salmon, as well as special guest appearances by Sam Bush, Holly Bowling, Jason Carter, Bronwyn Keith-Hynes, and Andy Thorn, who will play a special Mac Miller set. Note: Last year’s STL Atomic Block Party sold out.