I'll be going to Cabin Creek in September. While I know this was not the intent of your question, which meant Major Battlefields, I thought I might educate he public that there were quite a few battlefields in Indian Territory, just not the same size as the "big" ones and not as many died. But then if it was, then that was one too many,,,,

The Second Battle of Cabin Creek was a major victory for the South in Indian Territory and the Trans-Mississippi. General Stand Watie and Colonel Gano, attack a Union supply train headed to Ft Gibson. The attack resulted in two to three million dollars worth of supllies resupplying the Confederacy and not the Union.