| Official Name: | Diagonal, Iowa |
| Settlement Type: | City |
| Mapsize: | 250px |
| Subdivision Type: | Country |
| Subdivision Type1: | State |
| Subdivision Type2: | County |
| Subdivision Name2: | Ringgold |
| Unit Pref: | Imperial |
| Area Footnotes: | [1] |
| Area Total Km2: | 2.37 |
| Area Land Km2: | 2.36 |
| Area Water Km2: | 0.00 |
| Area Total Sq Mi: | 0.92 |
| Area Land Sq Mi: | 0.91 |
| Area Water Sq Mi: | 0.00 |
| Population As Of: | 2020 |
| Population Total: | 344 |
| Population Density Km2: | 145.47 |
| Population Density Sq Mi: | 376.78 |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Elevation Ft: | 1168 |
| Coordinates: | 40.8106°N -94.3419°W |
| Postal Code Type: | ZIP code |
| Postal Code: | 50845 |
| Area Code: | 641 |
| Blank Name: | FIPS code |
| Blank Info: | 19-21270 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 2394532 |
Diagonal is a city in northwest Ringgold County, Iowa, the United States. The population was 344 at the time of the 2020 census.[2]
The community was named for the fact that two railroads intersected diagonally near the town site.[3]
Diagonal is located 5 miles west of US Route 169 and approximately eight miles northwest of Mount Ayr. The Grand River flows past the east side of the town.[4]
According to the United States Census Bureau, the city has a total area of 0.9sqmi, all land.[5]
As of the census[6] of 2010, there were 330 people, 119 households, and 71 families living in the city. The population density was 366.7PD/sqmi. There were 145 housing units at an average density of 161.1/sqmi. The racial makeup of the city was 97.9% White, 0.3% African American, and 1.8% Native American.
There were 119 households, of which 24.4% had children under the age of 18 living with them, 51.3% were married couples living together, 6.7% had a female householder with no husband present, 1.7% had a male householder with no wife present, and 40.3% were non-families. 37.0% of all households were made up of individuals, and 17.6% had someone living alone who was 65 years of age or older. The average household size was 2.13 and the average family size was 2.79.
The median age in the city was 52.8 years. 15.8% of residents were under the age of 18; 6.3% were between the ages of 18 and 24; 16.9% were from 25 to 44; 24.9% were from 45 to 64; and 36.1% were 65 years of age or older. The gender makeup of the city was 45.2% male and 54.8% female.
As of the census[7] of 2000, there were 312 people, 139 households, and 87 families living in the city. The population density was 343.5sp=usNaNsp=us. There were 154 housing units at an average density of 169.6sp=usNaNsp=us. The racial makeup of the city was 100.00% White.
There were 139 households, out of which 23.0% had children under the age of 18 living with them, 54.0% were married couples living together, 5.8% had a female householder with no husband present, and 36.7% were non-families. 31.7% of all households were made up of individuals, and 16.5% had someone living alone who was 65 years of age or older. The average household size was 2.24 and the average family size was 2.85.
21.2% were under the age of 18, 10.9% from 18 to 24, 25.3% from 25 to 44, 24.4% from 45 to 64, and 18.3% were 65 years of age or older. The median age was 40 years. For every 100 females, there were 92.6 males. For every 100 females age 18 and over, there were 87.8 males.
The median income for a household in the city was $24,063, and the median income for a family was $28,393. Males had a median income of $22,083 versus $18,958 for females. The per capita income for the city was $16,601. About 16.5% of families and 15.8% of the population were below the poverty line, including 23.7% of those under age 18 and 13.3% of those age 65 or over.