| Official Name: | Groton, South Dakota |
| Settlement Type: | City |
| Mapsize: | 250px |
| Subdivision Type: | Country |
| Subdivision Name: | United States |
| Subdivision Type1: | State |
| Subdivision Name1: | South Dakota |
| Subdivision Type2: | County |
| Subdivision Name2: | Brown |
| Established Title3: | Incorporated |
| Established Date3: | 1888[1] |
| Unit Pref: | Imperial |
| Area Footnotes: | [2] |
| Area Total Km2: | 4.54 |
| Area Land Km2: | 4.54 |
| Area Water Km2: | 0.00 |
| Area Total Sq Mi: | 1.75 |
| Area Land Sq Mi: | 1.75 |
| Area Water Sq Mi: | 0.00 |
| Population As Of: | 2020 |
| Population Total: | 1380 |
| Population Density Km2: | 304.24 |
| Population Density Sq Mi: | 788.12 |
| Timezone: | Central (CST) |
| Utc Offset: | -6 |
| Timezone Dst: | CDT |
| Utc Offset Dst: | -5 |
| Coordinates: | 45.4517°N -98.1°W |
| Elevation Ft: | 1303 |
| Postal Code Type: | ZIP code |
| Postal Code: | 57445 |
| Area Code: | 605 |
| Blank Name: | FIPS code |
| Blank Info: | 46-26340 |
| Blank1 Name: | GNIS feature ID |
| Blank1 Info: | 1267410 |
Groton is a city in southeastern Brown County, South Dakota, United States. The population was 1,380 at the 2020 census.[3]
Groton was platted in 1881.[4] The city was named after Groton, Massachusetts.[5] A post office has been in operation at Groton since 1881.[6]
According to the United States Census Bureau, the city has a total area of 1.75sqmi, all land.[7]
As of the census[8] of 2010, there were 1,458 people, 576 households, and 373 families living in the city. The population density was 833.1PD/sqmi. There were 630 housing units at an average density of 360/sqmi. The racial makeup of the city was 97.5% White, 0.3% African American, 0.5% Native American, 0.1% Asian, 0.2% from other races, and 1.4% from two or more races. Hispanic or Latino of any race were 0.9% of the population.
There were 576 households, of which 34.4% had children under the age of 18 living with them, 56.1% were married couples living together, 6.4% had a female householder with no husband present, 2.3% had a male householder with no wife present, and 35.2% were non-families. 30.4% of all households were made up of individuals, and 15.4% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the average family size was 3.13.
The median age in the city was 40 years. 28.5% of residents were under the age of 18; 5.5% were between the ages of 18 and 24; 22.9% were from 25 to 44; 23.7% were from 45 to 64; and 19.4% were 65 years of age or older. The gender makeup of the city was 49.3% male and 50.7% female.
As of the census of 2000, there were 1,356 people, 524 households, and 372 families living in the city. The population density was 796.5sp=usNaNsp=us. There were 581 housing units at an average density of 341.3sp=usNaNsp=us. The racial makeup of the city was 99.04% White, 0.52% Native American, 0.07% from other races, and 0.37% from two or more races. Hispanic or Latino of any race were 0.44% of the population.
There were 524 households, out of which 35.7% had children under the age of 18 living with them, 59.7% were married couples living together, 8.8% had a female householder with no husband present, and 29.0% were non-families. 27.5% of all households were made up of individuals, and 14.7% had someone living alone who was 65 years of age or older. The average household size was 2.45 and the average family size was 2.99.
In the city, the population was spread out, with 27.8% under the age of 18, 5.7% from 18 to 24, 24.3% from 25 to 44, 20.2% from 45 to 64, and 22.0% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 88.3 males. For every 100 females age 18 and over, there were 83.0 males.
As of 2000 the median income for a household in the city was $38,125, and the median income for a family was $47,788. Males had a median income of $30,865 versus $21,688 for females. The per capita income for the city was $17,248. About 4.2% of families and 5.8% of the population were below the poverty line, including 5.5% of those under age 18 and 5.0% of those age 65 or over.