Yakima training center in Washington is about 327,000 acres, established 1941. Still a lot of bitterness with the locals over the eminent domain actions to establish it.
It hosts 1 of the 2 remaining populations of greater sage-grouse in WA, although the population isn't exactly thriving. They start a lot of fires that sometimes burn off range, not great for sage-grouse.
They used to allow some access for mule deer and elk, upland game birds, but google says they have suspended recreational access due to budget/staffing cuts.