Arnegard was founded with about 100 people living there, and it reached its peak population of 254 in 1930. The town weathered the Great Depression well enough, but by 1940 the population was down to just 222 (a loss of 12.5 percent). The population stayed relatively steady until 1960, but dropped by almost 40 percent to just 141 people in 1970. A brief surge in population during the 1970s oil boom (oil and natural gas deposits were found beneath McKenzie County about 1974), but the boom was followed by a bust in 1980 as drillers discovered that most of the oil was locked in shale which (at the time) could not be reached. By 1990, the population was 122, and by 2000 it was just 105. Arnegard has seen a small uptick in population in the 2000s attributable to the North Dakota Oil Boom.