Arnold was laid out and platted in 1883 in anticipation that the railroad would soon be extended to that point. However, the railroad failed to materialize and Arnold grew slowly until the railroad finally arrived in 1912.
As of the census of 2010, there were 597 people, 295 households, and 166 families living in the village. The population density was. There were 348 housing units at an average density of. The racial makeup of the village was 98.5% White, 0.2% African American, 0.3% from other races, and 1.0% from two or more races. Hispanic or Latino of any race were 1.8% of the population. There were 295 households, of which 20.3% had children under the age of 18 living with them, 47.8% were married couplesliving together, 5.4% had a female householder with no husband present, 3.1% had a male householder with no wife present, and 43.7% were non-families. 41.4% of all households were made up of individuals, and 21.7% had someone living alone who was 65 years of age or older. The average household size was 2.02 and the average family size was 2.71. The median age in the village was 48.3 years. 19.9% of residents were under the age of 18; 6.6% were between the ages of 18 and 24; 19.2% were from 25 to 44; 28.1% were from 45 to 64; and 26.3% were 65 years of age or older. The gender makeup of the village was 49.1% male and 50.9% female.
2000 census
As of the census of 2000, there were 630 people, 303 households, and 180 families living in the village. The population density was 814.7 people per square mile. There were 351 housing units at an average density of 453.9 per square mile. The racial makeup of the village was 98.73% White, 0.48% Native American, 0.48% from other races, and 0.32% from two or more races. Hispanic or Latino of any race were 1.75% of the population. There were 303 households, out of which 25.4% had children under the age of 18 living with them, 52.1% were married couples living together, 5.6% had a female householder with no husband present, and 40.3% were non-families. 37.6% of all households were made up of individuals, and 20.5% had someone living alone who was 65 years of age or older. The average household size was 2.08 and the average family size was 2.73. In the village, the population was spread out, with 23.0% under the age of 18, 5.7% from 18 to 24, 22.5% from 25 to 44, 23.8% from 45 to 64, and 24.9% who were 65 years of age or older. The median age was 44 years. For every 100 females, there were 90.3 males. For every 100 females age 18 and over, there were 84.4 males. As of 2000 the median income for a household in the village was $25,500, and the median income for a family was $35,875. Males had a median income of $24,375 versus $21,339 for females. The per capita income for the village was $18,574. About 10.1% of families and 14.8% of the population were below the poverty line, including 28.2% of those under age 18 and 8.3% of those age 65 or over.
