Elgin is located at at the confluence of Otter Creek with the Turkey River. According to the United States Census Bureau, the city has a total area of, all land. Elgin and the neighboring towns of Clermont and Wadena made up the Valley Community School district. Due to diminishing class sizes and less aid from the state of Iowa, Valley combined services in 2013 with the nearby North Fayette School district, which comprises the towns of West Union, Hawkeye and Fayette and the combined district is now called North Fayette Valley, with the middle school being in Elgin and the high school located in West Union. The school's mascot is now called the Tigerhawks. This sharing program will last until the 2015-2016 school year.
As of the census of 2010, there were 683 people, 318 households, and 191 families living in the city. The population density was. There were 343 housing units at an average density of. The racial makeup of the city was 98.8% White, 0.1% African American, 0.4% Native American, 0.1% from other races, and 0.4% from two or more races. Hispanic or Latino of any race were 1.0% of the population. There were 318 households, of which 25.2% had children under the age of 18 living with them, 48.1% were married couplesliving together, 6.9% had a female householder with no husband present, 5.0% had a male householder with no wife present, and 39.9% were non-families. 36.2% of all households were made up of individuals, and 17.7% had someone living alone who was 65 years of age or older. The average household size was 2.15 and the average family size was 2.75. The median age in the city was 43.8 years. 23.3% of residents were under the age of 18; 8.4% were between the ages of 18 and 24; 19.7% were from 25 to 44; 25.3% were from 45 to 64; and 23.3% were 65 years of age or older. The gender makeup of the city was 49.3% male and 50.7% female.
2000 census
As of the census of 2000, there were 676 people, 327 households, and 182 families living in the city. The population density was 1,011.3 people per square mile. There were 349 housing units at an average density of 522.1 per square mile. The racial makeup of the city was 99.85% White, 0.15% from other races. Hispanic or Latino of any race were 0.30% of the population. There were 327 households, out of which 22.6% had children under the age of 18 living with them, 45.3% were married couples living together, 8.6% had a female householder with no husband present, and 44.3% were non-families. 37.9% of all households were made up of individuals, and 25.4% had someone living alone who was 65 years of age or older. The average household size was 2.07 and the average family size was 2.70. In the city, the population was spread out, with 20.7% under the age of 18, 7.4% from 18 to 24, 23.1% from 25 to 44, 19.7% from 45 to 64, and 29.1% who were 65 years of age or older. The median age was 44 years. For every 100 females, there were 91.0 males. For every 100 females age 18 and over, there were 84.2 males. The median income for a household in the city was $28,833, and the median income for a family was $38,571. Males had a median income of $28,750 versus $21,979 for females. The per capita income for the city was $16,225. About 6.9% of families and 7.8% of the population were below the poverty line, including 4.0% of those under age 18 and 17.1% of those age 65 or over.
