12 Tribes Lake Chelan Casino is a local casino, RV park and outdoor concert venue in Manson, WA. The 12 Tribes Lake Chelan Casino’s Amphitheater offers a unique structure as the Pacific Northwest’s only outdoor concert venue with covered seating. Join over 1,500 others in the powerful all-in experience. Locates casinos near Interstate I-5 with. Locates casinos near Interstate I-5 with distance from highway exit and travel time. The Indian Gaming Regulatory Act IGRA, passed by Congress in 1988, requires states to negotiate gaming compacts in good faith to allow tribes to offer casino-style gaming if it is allowed in the state.This map was created by a user. Washington Casinos: Map of the Best Gambling Locations in WA.