Arthur County was established in 1913 from the western part of McPherson County following an effort to move the McPherson County seat from Tryon to the more centrally located Flats: rather than lose the county seat, the residents of Tryon, Nebraska agreed to have the county divided approximately in half, according to boundaries for sandhills counties originally proposed in 1887. The half which became Arthur County had been in the process of settlement by 1884, by ranchers seeking open grazing land. The placement of a post office at Lena in 1894 and the passage of the homesteading act in 1904 further influenced the county's founding and expedited the new county's establishment processes. The new county was named after President Chester A. Arthur, and the village of Arthur, similarly named, was established to serve as the county seat. Principal postal service moved from Lena to the village of Arthur in 1914, which also held the county's public schools, general store, bank and co-op, principal churches, newspaper and other businesses and services, all aimed at continuing and facilitating the county's rural lifestyle. The 1920 United States Census counted 1,412 residents in Arthur County, which was then and has remained entirely rural, essentially ranching. Although the village of Arthur underwent electrification in the 1920s, most of the county did not see power or telephone services until 1950–1951. At that time also, highway construction and improvements facilitated transportation, which was especially dependent upon the north-south State Highway 61 and the east-west Highway 92: motor vehicles were the sole means of mechanical transportation throughout Arthur's history as it had no railroad or canal. Irrigation of the sandhills land started by 1900 and continued through the first half of the twentieth century, with center-pivot irrigation dominating. The population peaked around 1930 at 1,344 persons, but declined with the Great Depression. By 1950, the county population was down to 803, by 1980 down to 513.
Geography
According to the US Census Bureau, the county has an area of, of which is land and is water.
As of the 2000 United States Census, of 2000, there were 444 people, 185 households, and 138 families residing in the county. The population density was 0.618 people per square mile. There were 273 housing units at an average density of 0.380 per square mile. The racial makeup of the county was 96.40% White, 0.23% Native American, 0.68% Asian, 0.23% Pacific Islander, 0.90% from other races, and 1.58% from two or more races. 1.35% of the population were Hispanic or Latino of any race. 50.4% were of German, 13.1% English, 6.2% Irish and 5.7% Swedish ancestry. There were 185 households out of which 27.60% had children under the age of 18 living with them, 63.20% were married couplesliving together, 7.60% had a female householder with no husband present, and 25.40% were non-families. 21.60% of all households were made up of individuals and 10.80% had someone living alone who was 65 years of age or older. The average household size was 2.40 and the average family size was 2.80. The county population contained 23.90% under the age of 18, 5.40% from 18 to 24, 29.50% from 25 to 44, 24.80% from 45 to 64, and 16.40% who were 65 years of age or older. The median age was 40 years. For every 100 females there were 101.80 males. For every 100 females age 18 and over, there were 107.40 males. The median income for a household in the county was $27,375, and the median income for a family was $31,979. Males had a median income of $21,544 versus $13,125 for females. The per capita income for the county was $15,810. About 7.90% of families and 13.80% of the population were below the poverty line, including 15.10% of those under age 18 and 7.80% of those age 65 or over.
Religion
More than 50% of the county residents are Baptists, making it the northernmost most Baptist majority county in the United States.
