This Osage Casino is located at 2017 East 15th Street at Highway 99 just east of Pawhuska, Oklahoma. The casino has a 5,400 square foot gaming floor with 180 slot machines. This is a very small casino at just over 5,000 square feet, but Pawhuska is the Osage Nation Headquarters and the casino was originally opened in the spring of 2003. The casino is open until 2am Sunday through Tuesday and until 4am all other nights. You must be 18 to gamble here.