ProKart Challenge to host round five at Sonoma Raceway ProKart Challenge to host round five at Sonoma Raceway Superkarts! USA returning to northern California for first time since 2017 with regional program Bas Kaligis / Thursday, August 14, 2025 0 62 Article rating: No rating A significant weekend lies ahead for the ProKart Challenge program. The Superkarts! USA regional program is set to host Round Five of the 2025 schedule on August 23-24 at Sonoma Raceway. The weekend marks the first trip to the Sonoma, California facility for the organization since 2017 when they hosted the SKUSA Pro Tour SpringNationals. Read more