| Official Name: | Duncan, Iowa |
| Settlement Type: | Census-designated place |
| Pushpin Map: | Iowa#USA |
| Pushpin Label: | Duncan |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name: | United States |
| Subdivision Name1: | Iowa |
| Subdivision Name2: | Hancock |
| Area Total Km2: | 2.05 |
| Area Total Sq Mi: | 0.79 |
| Area Land Km2: | 2.03 |
| Area Land Sq Mi: | 0.79 |
| Area Water Km2: | 0.02 |
| Area Water Sq Mi: | 0.01 |
| Elevation Ft: | 1237 |
| Population As Of: | 2020 |
| Population Total: | 57 |
| Population Density Km2: | 28.02 |
| Population Density Sq Mi: | 72.61 |
| Timezone: | CST |
| Utc Offset: | -6 |
| Coordinates: | 43.1044°N -93.7111°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 50423 |
| Area Code: | 641 |
| Blank Name: | FIPS code |
| Blank Info: | 19-22710 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 0456058 |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
Duncan is a census-designated place (CDP) in Hancock County, Iowa, United States. The population was 57 at the 2020 census.
Duncan was platted in 1900.[2] The community's population was 25 in 1902,[3] and 20 in 1925.[4] The population was 75 in 1940.[5]
Duncan is located at 43.1044°N -93.7111°W,[6] east of Britt and west of Garner, along U.S. Route 18.
According to the United States Census Bureau, the CDP has a total area of 2.05sqkm, of which 2.03sqkm is land and 0.02sqkm, or 0.90%, is water.[7]
As of the census of 2020,[8] there were 57 people, 32 households, and 23 families residing in the community. The population density was 72.6 inhabitants per square mile (28.0/km2). There were 32 housing units at an average density of 40.7 per square mile (15.7/km2). The racial makeup of the community was 98.2% White, 0.0% Black or African American, 0.0% Native American, 0.0% Asian, 0.0% Pacific Islander, 0.0% from other races and 1.8% from two or more races. Hispanic or Latino persons of any race comprised 0.0% of the population.
Of the 32 households, 37.5% of which had children under the age of 18 living with them, 68.8% were married couples living together, 9.4% were cohabitating couples, 3.1% had a female householder with no spouse or partner present and 18.8% had a male householder with no spouse or partner present. 28.1% of all households were non-families. 21.9% of all households were made up of individuals, 9.4% had someone living alone who was 65 years old or older.
The median age in the community was 48.3 years. 17.5% of the residents were under the age of 20; 1.8% were between the ages of 20 and 24; 26.3% were from 25 and 44; 24.6% were from 45 and 64; and 29.8% were 65 years of age or older. The gender makeup of the community was 63.2% male and 36.8% female.
Duncan is a part of the Garner–Hayfield–Ventura Community School District. It was previously in the Garner–Hayfield Community School District,[9] which merged into the current GHV district on July 1, 2015.[10]