Milroy was platted in 1902, and named for Robert H. Milroy, a Union Army general in the AmericanCivil War. A post office has been in operation at Milroy since 1902. Milroy was incorporated in 1902.
As of the census of 2010, there were 252 people, 114 households, and 66 families living in the city. The population density was. There were 127 housing units at an average density of. The racial makeup of the city was 98.4% White, 1.2% Asian, and 0.4% from two or more races. Hispanic or Latino of any race were 0.8% of the population. There were 114 households of which 24.6% had children under the age of 18 living with them, 50.0% were married couplesliving together, 0.9% had a female householder with no husband present, 7.0% had a male householder with no wife present, and 42.1% were non-families. 36.8% of all households were made up of individuals and 5.3% had someone living alone who was 65 years of age or older. The average household size was 2.21 and the average family size was 2.92. The median age in the city was 37 years. 23.4% of residents were under the age of 18; 9.1% were between the ages of 18 and 24; 28.4% were from 25 to 44; 26.9% were from 45 to 64; and 11.9% were 65 years of age or older. The gender makeup of the city was 51.2% male and 48.8% female.
2000 census
As of the census of 2000, there were 271 people, 119 households, and 76 families living in the city. The population density was 1,066.0 people per square mile. There were 132 housing units at an average density of 519.2 per square mile. The racial makeup of the city was 97.42% White, 0.74% Native American, 0.74% Asian, and 1.11% from other races. Hispanic or Latino of any race were 1.85% of the population. There were 119 households out of which 28.6% had children under the age of 18 living with them, 45.4% were married couples living together, 12.6% had a female householder with no husband present, and 36.1% were non-families. 33.6% of all households were made up of individuals and 11.8% had someone living alone who was 65 years of age or older. The average household size was 2.28 and the average family size was 2.87. In the city, the population was spread out with 26.9% under the age of 18, 6.3% from 18 to 24, 26.2% from 25 to 44, 23.2% from 45 to 64, and 17.3% who were 65 years of age or older. The median age was 40 years. For every 100 females, there were 122.1 males. For every 100 females age 18 and over, there were 104.1 males. The median income for a household in the city was $33,625, and the median income for a family was $36,042. Males had a median income of $29,722 versus $18,750 for females. The per capita income for the city was $16,866. About 5.2% of families and 9.3% of the population were below the poverty line, including 22.4% of those under the age of eighteen and none of those sixty five or over.
