Fairfield is the county seat of and the only city in Camas County, Idaho, United States. The population was 416 at the 2010 census, nearly half of the rural county's population. The town was also featured in a season 2 episode of the X-Files, whereupon an investigation at a fictitious zoo took place.
As of the census of 2020, there were 414 people, 176 households, and 109 families residing in the city. The population density was. There were 244 housing units at an average density of. The racial makeup of the city was 93.0% White, 1.0% Native American, 0.2% Asian, 1.4% from other races, and 4.3% from two or more races. Hispanic or Latino of any race were 6.3% of the population. There were 176 households, of which 35.2% had children under the age of 18 living with them, 44.9% were married couplesliving together, 6.8% had a female householder with no husband present, 10.2% had a male householder with no wife present, and 38.1% were non-families. 31.8% of all households were made up of individuals, and 9.1% had someone living alone who was 65 years of age or older. The average household size was 2.36 and the average family size was 2.95. The median age in the city was 35.1 years. 26.4% of residents were under the age of 18; 5.6% were between the ages of 18 and 24; 29.6% were from 25 to 44; 27.4% were from 45 to 64; and 11.1% were 65 years of age or older. The gender makeup of the city was 51.9% male and 48.1% female.
2000 census
As of the census of 2000, there were 395 people, 162 households, and 115 families residing in the city. The population density was 1,214.3 people per square mile. There were 211 housing units at an average density of 648.7 per square mile. The racial makeup of the city was 97.97% White, 0.51% Native American, 0.25% from other races, and 1.27% from two or more races. Hispanic or Latino of any race were 6.08% of the population. There were 162 households, out of which 33.3% had children under the age of 18 living with them, 60.5% were married couples living together, 6.8% had a female householder with no husband present, and 29.0% were non-families. 25.3% of all households were made up of individuals, and 11.1% had someone living alone who was 65 years of age or older. The average household size was 2.44 and the average family size was 2.92. In the city, the population was spread out, with 25.6% under the age of 18, 7.3% from 18 to 24, 27.1% from 25 to 44, 27.6% from 45 to 64, and 12.4% who were 65 years of age or older. The median age was 39 years. For every 100 females, there were 96.5 males. For every 100 females age 18 and over, there were 94.7 males. The median income for a household in the city was $31,167, and the median income for a family was $33,750. Males had a median income of $26,607 versus $16,667 for females. The per capita income for the city was $21,504. About 9.1% of families and 10.7% of the population were below the poverty line, including 6.7% of those under age 18 and 18.0% of those age 65 or over.
