While the name's usage can be traced to the early part of the 20th century,[1] it was popularized in the 1960s by the Oklahoma Department of Tourism and Recreation as one of six travel destination regions within the state.
Said tourism designation is an 18-county region including Pawnee, Osage, Washington, Nowata, Craig, Ottawa, Delaware, Mayes, Rogers, Creek, Tulsa, Wagoner, Cherokee, Adair, Sequoyah, Muskogee, Okmulgee, and McIntosh counties.
[3] The heavily wooded Ozark Mountains and their foothills dominate most of northeast Oklahoma from the immediate Tulsa vicinity south and eastward towards the Arkansas state line, containing both evergreen pine and deciduous forests.
In its western counties, the far eastern extent of the Great Plains transition to woodlands through the Cross Timbers region.
[citation needed] Based on commuting patterns, the adjacent micropolitan area of Bartlesville, is grouped together in the (CSA).
Interstate 44 is the primary thoroughfare and runs diagonally through Green Country, exiting on the southwest and northeast corners.