Marmarth (/ˈmɑːrməθ/ MAR-məth) is the largest city in Slope County in the U.S. State of North Dakota with a population of 101 as of 2020 census.

[5] The town is recognized for various historical events, including Native-American Lakota history, the discovery of the Dakota fossil and various other dinosaur skeletons, the attack on James L. Fisk by Sitting Bull, and several visits by former president Theodore Roosevelt.

Marmarth is adjacent to the Little Missouri National Grassland, and is also the closest city to Big Gumbo, a 20,000 acre federally owned public wilderness area administrated by the Bureau of Land Management.

[11] It is nicknamed the “city of trees”, as a result of being one of few forested areas in the Badlands region of Southern North Dakota.

[16] The area was originally inhabited by the Lakota- and Crow peoples,[17] which may have been part of the 9th–12th centuries BCE Mound Builders civilization.

[18] On September 2, 1864, Captain James L. Fisk of the Union Army was leading 200 gold-seekers in eighty-eight wagons from North Dakota to Montana.

By the Deep Creek, approximately twelve miles east of today's Marmarth, the group was attacked by over a hundred Hunkpapa Sioux Indians led by the chief Sitting Bull.

[19][20] Theodore Roosevelt was frequently in Marmarth and it is credited as the place where the future president shot his first grizzly bear and also his first buffalo.

Marmarth was a hugely popular place for homesteading during the late 19th and early 20th centuries, and was founded in the fall of 1907 as a result of the new Milwaukee Road transcontinental rail line known as the Pacific Extension, as well as other factors such as agriculture, and cheap land.

The town was originally laid out on the east side of the Little Missouri River, near where a post office known as Neva and a hotel had already been established.

Because the first two decades of the 20th century were unusually wet, the new settlers reaped harvests of wheat on a scale "that promised to turn even owners of modest farms into wealthy men.

[23] During a spring thaw in April 1920, rural Marmarth rancher Jack Miller fled his home on horseback to escape the flooding Beaver Creek.

[26] When his horse slipped Miller, who had just one arm, found himself swimming in icy waters until he was able to climb aboard an iceberg.

[26] Miller managed to anchor the iceberg against a tree, and he danced on the berg all night in order to stay awake and avoid freezing.

The town was also known to jail the notorious Jesse James’ gang, consisting of the Old West outlaws Cole, Bob, and Jim.

[27] By the 1920s, a combination of the end of the agricultural boom occasioned by World War I and a return to more normal (i.e., drier) climatic conditions drove many of the settlers from their farms.

The area surrounding Marmarth in southern Theodore Roosevelt National Park is home to a large variety of wildlife species, including the pronghorn antelope, black-tailed prairie dog, feral horse, bison, bighorn sheep, elk, white-tailed deer, mule deer, wild turkey, bull snake, prairie rattlesnake, and avifauna such as the ferruginous hawk, golden eagle, greater sage-grouse, mountain bluebird, Brewer's sparrow, burrowing owl, lark bunting, chestnut-collared longspur, long-billed curlew, red-tailed hawk, common poorwill, chickadee, spotted towhee, lazuli bunting, and Clark's nutcracker.