A post office was established at Kelley in 1875, and remained in operation until it was discontinued in 2013. The city was named for J. T. Kelly, land owner.
As of the census of 2010, there were 309 people, 120 households, and 91 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, 0.6% African American, 0.3% Asian, and 0.6% from two or more races. Hispanic or Latino of any race were 1.0% of the population. There were 120 households, of which 37.5% had children under the age of 18 living with them, 57.5% were married couplesliving together, 13.3% had a female householder with no husband present, 5.0% had a male householder with no wife present, and 24.2% were non-families. 20.0% of all households were made up of individuals, and 3.3% had someone living alone who was 65 years of age or older. The average household size was 2.58 and the average family size was 2.96. The median age in the city was 35.1 years. 26.9% of residents were under the age of 18; 9.3% were between the ages of 18 and 24; 26.8% were from 25 to 44; 27.5% were from 45 to 64; and 9.4% were 65 years of age or older. The gender makeup of the city was 50.2% male and 49.8% female.
2000 census
As of the census of 2000, there were 300 people, 109 households, and 80 families living in the city. The population density was 1,072.7 people per square mile. There were 113 housing units at an average density of 404.1 per square mile. The racial makeup of the city was 99.00% White, 0.33% Native American, and 0.67% from two or more races. There were 109 households, out of which 41.3% had children under the age of 18 living with them, 63.3% were married couples living together, 8.3% had a female householder with no husband present, and 25.7% were non-families. 22.0% of all households were made up of individuals, and 6.4% had someone living alone who was 65 years of age or older. The average household size was 2.75 and the average family size was 3.25. In the city, the population was spread out, with 32.3% under the age of 18, 7.3% from 18 to 24, 38.0% from 25 to 44, 16.7% from 45 to 64, and 5.7% who were 65 years of age or older. The median age was 32 years. For every 100 females, there were 98.7 males. For every 100 females age 18 and over, there were 91.5 males. The median income for a household in the city was $54,375, and the median income for a family was $57,344. Males had a median income of $31,964 versus $22,000 for females. The per capita income for the city was $17,574. None of the families and 1.0% of the population were living below the poverty line.
