Question: The largest county in Oklahoma by area, gets its name from the broad rolling hills and rolling tallgrass prairie and Cross Timbers encompassing the county and surrounding areas, including portions of Mayes, Tulsa, Washington and Kay Counties, was created in what year?
Sentence (from "Skiatook Lake"): Skiatook Lake is a federally-owned and operated reservoir located in Osage County, Oklahoma, 4 mi west of the town of Skiatook, 11 mi east of Hominy, Oklahoma and about 18 mi from Tulsa.
Relevant evidence: No