| Official Name: | South Middletown, Ohio |
| Settlement Type: | Former CDP |
| Mapsize: | 250px |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | Ohio |
| Subdivision Type2: | County |
| Subdivision Name2: | Butler |
| Unit Pref: | Imperial |
| Area Total Km2: | 0.3 |
| Area Land Km2: | 0.3 |
| Area Water Km2: | 0.0 |
| Area Total Sq Mi: | 0.1 |
| Area Land Sq Mi: | 0.1 |
| Area Water Sq Mi: | 0.0 |
| Population As Of: | 2000 |
| Population Total: | 264 |
| Population Density Km2: | 954.5 |
| Population Density Sq Mi: | 2472.2 |
| Timezone: | Eastern (EST) |
| Utc Offset: | -5 |
| Timezone Dst: | EDT |
| Utc Offset Dst: | -4 |
| Elevation Footnotes: | [1] |
| Elevation M: | 194 |
| Elevation Ft: | 636 |
| Coordinates: | 39.4819°N -84.4128°W |
| Blank Name: | FIPS code |
| Blank Info: | 39-73510[2] |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 1867468 |
South Middletown is a former census-designated place (CDP) in Lemon Township, Butler County, Ohio, United States. The population was 264 at the 2000 census. The area of South Middletown is now within the city limits of Middletown.
South Middletown is located at 39.4819°N -84.4128°W (39.481858, -84.412822).[3]
According to the United States Census Bureau, the CDP had a total area of 0.1sqmi, all land.
As of the census of 2000, there were 264 people, 96 households, and 62 families residing in the CDP. The population density was 2472.2sp=usNaNsp=us. There were 107 housing units at an average density of 1002sp=usNaNsp=us. The racial makeup of the CDP was 98.11% White, 0.38% African American, and 1.52% from two or more races. Hispanic or Latino of any race were 0.76% of the population.
There were 96 households, out of which 30.2% had children under the age of 18 living with them, 51.0% were married couples living together, 9.4% had a female householder with no husband present, and 34.4% were non-families. 25.0% of all households were made up of individuals, and 10.4% 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 3.38.
In the CDP the population was spread out, with 31.8% under the age of 18, 10.2% from 18 to 24, 29.5% from 25 to 44, 18.6% from 45 to 64, and 9.8% who were 65 years of age or older. The median age was 31 years. For every 100 females, there were 84.6 males. For every 100 females age 18 and over, there were 83.7 males.
The median income for a household in the CDP was $45,750, and the median income for a family was $45,750. Males had a median income of $32,500 versus $24,333 for females. The per capita income for the CDP was $19,620. None of the families and 5.7% of the population were living below the poverty line.