Marmarth is the largest city in Slope County in the U.S. State of North Dakota with a population of 143 as of 2014. It is situated in the southwestern part of Slope County, along the Bowman County-limits, in the southwestern part of North Dakota, just seven miles east of the state-border to Montana. Marmarth was founded as a railroad town along the Milwaukee Road from Seattle, WA to Chicago, IL, in order to develop a town for homesteaders. By its founding, the town population was over 5,000 people - mostly rail workers and cattle ranchers. Despite a population boom caused by the opening of the Little Beaver Dome oil field in 1936, the town population declined during most of the 21st century and had a population of only 143 in 2014. There is one restaurant and one bar still located in Marmarth in 2013.