Slope County, ND borders Billings near Marmarth metropolitan centre giving a 2020 estimated census population standing of 765 making it the 5th least populous county located in North Dakota overall. Its county seat is Marmarth with other cities include Amidon & Burtons Corner-Marmarth itself corresponds out to Slope's largestcity aside from acknowledged country seat. This area had been established from Stark and Golden Valley Counties back in 1915 when local citizens petitioned for new administrative boundaries - posthumously named after the local topography composed of rolling hillsforms .