are the primary range in the area. Northeast Oklahoma has a land area of , comprising 18 entire counties. The region comprises about 19.3 percent of Oklahoma's land area, and is larger than the state of Maryland. Political geography Based on commuting patterns, the adjacent micropolitan area of Bartlesville, is grouped together in the (CSA). The population of this wider region is 998,438—more than one-fourth of Oklahoma's population—as of 2012. The 2010 census population of Green Country was 1,301,716 inhabitants, about 30 percent of whom were concentrated in the city of Tulsa. Counties of the Green Country region (per Oklahoma Department of Tourism and Recreation) Adair County Craig County Creek County Cherokee County Delaware County Mayes County McIntosh County Muskogee County Nowata County Okmulgee County Osage County Ottawa County Pawnee County Rogers County Sequoyah County Tulsa County Wagoner County Washington County It includes the Deep Fork National Wildlife Refuge, Ozark Plateau National Wildlife Refuge, Arkansas River, Canadian River, Grand River, Illinois River, and Verdigris River. Infrastructure The Tulsa International Airport is the primary commercial flight operation in Green Country. Also in the area, the Tulsa Port of Catoosa and Port of Muskogee are Oklahoma's only seaports, connecting the state directly with international trade routes. From either of these two ports, goods may be transported via the Arkansas River's connection to the Mississippi River. The area's highway system is dominated by turnpikes. Toll roads account for the primary highways in and out of the city of Tulsa in almost every direction. The Will Rogers Turnpike serves the city to the northeast, the Turner Turnpike to the southwest, the Cimarron Turnpike to the west, The Muskogee Turnpike to the southeast, and the Cherokee Turnpike to the east. Interstate 44 is the primary thoroughfare, and runs diagonally through Green Country, exiting on the southwest and northeast corners. All portions of the road through northeastern Oklahoma exists as a toll road, except for in the city of Tulsa. Interstate 40 straddles the southernmost border of Green Country, while other highways include the north-south Highway 75 (not a turnpike), The Muskogee Turnpike, the north-south Highway 69, Highway 169, and the east-west Highway 412. In addition, Historic U.S. Route 66 runs (with breaks) between the Kansas line and Stroud, the southwesternmost town in the region. Cities and towns Tulsa Owasso Broken Arrow Bartlesville Jenks Bixby Skiatook Claremore Cleveland Okmulgee Muskogee Miami Tahlequah Vinita Pryor Oologah Sapulpa