OKOklahoma Geography

No Man's Land and the county that touches four states

The Oklahoma Panhandle is a strip 166 miles long and about 34 miles deep, and it exists because of a line of latitude. Texas once claimed the ground, but the Missouri Compromise barred slavery north of 36 degrees 30 minutes, so when Texas sold off its northern claims in 1850 it kept nothing above that parallel. What was left over belonged to no state and no territory. Maps called it the Public Land Strip, cattlemen called it No Man's Land, and for forty years it had no courts, no sheriff and no legal way to file a claim on a piece of ground. The Organic Act finally attached it to Oklahoma Territory in 1890.

At the far western tip sits Cimarron County, the only county in the United States that borders four other states: Kansas, Colorado, New Mexico and Texas. The village of Kenton out there keeps Mountain Time, the only community in Oklahoma that does, an informal habit that follows the sun rather than the statute book. Every other clock in the state runs on Central.

Black Mesa down to the Little River

Oklahoma tilts from northwest to southeast, and both ends of that tilt are worth naming. The high point is Black Mesa at 4,973 feet, in the same Cimarron County corner, a flat-topped ridge armored with black basalt from a lava flow that spilled out of New Mexico several million years ago. The lava proved harder than the sandstone around it, everything softer eroded away, and the flow was left standing as a table. A granite obelisk marks the summit at the end of an eight-mile round trip on foot.

The low point lies diagonally opposite at 289 feet, where the Little River crosses into Arkansas below Idabel. The 4,684-foot difference between the two is close to a vertical mile, but it is spread over roughly 550 miles of slowly descending plain, which is why no road in Oklahoma feels like a mountain pass.

Four mountain ranges in a state people picture as flat

• The Wichita Mountains in the southwest are granite and gabbro roughly half a billion years old, among the oldest exposed rock on the continent. Mount Scott reaches 2,464 feet. The wildlife refuge wrapped around them holds a bison herd descended from fifteen animals shipped west from the Bronx Zoo in 1907.
• The Arbuckle Mountains in the south are the worn stumps of a far taller range. Interstate 35 slices straight through steeply tilted limestone beds near Davis, one of the most photographed roadcuts in American geology, and Turner Falls drops 77 feet a few miles away.
• The Ouachita Mountains in the southeast run east to west, which almost no other range in North America does. They were folded that way when landmasses collided from the south. Rich Mountain on the Arkansas line rises to about 2,680 feet, and the Talimena Drive follows the crest of Winding Stair Mountain.
• The Ozark Plateau in the northeast is not a range at all but a limestone upland that rivers have cut into hills, leaving caves, sinkholes and cold springs along the Illinois and Grand rivers.

Two rivers out, and more reservoirs than any other state

Every drop that falls on Oklahoma leaves through either the Arkansas River or the Red River. The Red forms the whole southern boundary with Texas and has been litigated harder than any other line in the state. In 1896 the Supreme Court had to decide which fork of the Red counted as the boundary, and awarded Greer County to Oklahoma Territory rather than Texas. In the 1920s the Court fixed the border at the south cut bank, which put the sandy riverbed itself inside Oklahoma, a detail that stopped being academic the moment oil was found under it.

The Arkansas River carries barges. The McClellan-Kerr Arkansas River Navigation System opened in 1971 and runs 445 miles from the Tulsa Port of Catoosa to the Mississippi, so grain and steel loaded at a dock in a landlocked state reach the Gulf of Mexico without ever touching a truck. Oklahoma also has more than 200 artificial lakes and almost no natural ones. Lake Eufaula, closed off on the Canadian River in 1964, spreads across about 102,500 acres.

Rainfall that halves across the state

Southeastern McCurtain County collects more than 55 inches of rain in an average year. The western Panhandle collects under 17. The 100th meridian, the old dividing line between the humid east and the dry west, crosses Oklahoma near Sayre and Erick, and the vegetation changes as you pass it: pine and hardwood forest in the southeast, tallgrass prairie through the middle, shortgrass and sand sage at the western end.

The state sits in the heart of Tornado Alley. On 3 May 1999 a mobile Doppler radar measured winds of roughly 301 miles per hour inside the tornado that tore through Bridge Creek and Moore, the fastest wind ever recorded near the ground anywhere on Earth. Oklahoma's temperature records run from 120 degrees, logged at Tipton, Alva and several other sites, down to 31 below zero at Nowata on 10 February 2011.

Salt, gypsum and sand

Three pieces of Oklahoma landscape have no real equivalent elsewhere. The Great Salt Plains in Alfalfa County are a glaring white flat left behind by an evaporated sea, and the mud beneath them grows hourglass selenite crystals, a form found nowhere else in the world; the state park allows visitors to dig for them in season. Alabaster Caverns near Freedom is billed as the largest natural gypsum cave open to the public anywhere. And at Little Sahara, outside Waynoka, dunes up to 75 feet high sit on old Cimarron River sand that the wind keeps rearranging.

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