Justin is a city in Denton County, Texas, United States. The population was 3,246 at the 2010 census.
According to the United States Census Bureau, the city has a total area of 2.4 square miles (6.2 km), all of it land.
Some areas along FM 156 and Hwy 114 use the Justin ZIP code (76247) even though the land is within the City of Fort Worth.
As of the census of 2000, there were 1,891 people, 650 households, and 503 families residing in the city. The population density was 796.8 people per square mile (308.1/km²). There were 681 housing units at an average density of 287.0/sq mi (110.9/km²). The racial makeup of the city was 94.44% White, 1.43% African American, 0.54% Native American, 0.49% Asian, 2.55% from other races, and 0.58% from two or more races.
There were 650 households out of which 41.8% had children under the age of 18 living with them, 66.5% were married couples living together, 8.3% had a female householder with no husband present, and 22.5% were non-families. 19.4% of all households were made up of individuals and 9.1% had someone living alone who was 70 years of age or older. The average household size was 2.75 and the average family size was 3.15.
In the city, the population was spread out with 27.7% under the age of 18, 8.1% from 18 to 24, 31.4% from 25 to 44, 18.8% from 45 to 69, and 13.9% who were 70 years of age or older. The median age was 35 years. For every 100 females, there were 91.3 males. For every 100 females age 18 and over, there were 82.7 males.
The median income for a household in the city was $52,257, and the median income for a family was $61,328. Males had a median income of $46,688 versus $27,805 for females. The per capita income for the city was $22,305. About 6.0% of families and 7.8% of the population were below the poverty line, including 9.5% of those under age 18 and 16.7% of those age 70 or over.
The Justin Fire Department covers the City of Justin and the approximately 88 surrounding square miles of unincorporated Denton County.