is a city in Hidalgo County, Texas. The population was 4,002 at the 2010 United States Census. It is part of the McAllen–Edinburg–Mission and Reynosa–McAllen metropolitan
Sullivan City is located at:
26°16′30″N 98°34′6″W / 26.27500°N 98.56833°W / 26.27500; -98.56833 (26.275087, -98.568330).
According to the United States Census Bureau, the city has a total area of 3.6 square miles (9.3 km2), all land.
As of the census of 2000, there were 3,998 people, 981 households, and 909 families residing in the city. The population density was 1,117.1 people per square mile (431.2/km²). There were 1,136 housing units at an average density of 317.4 per square mile (122.5/km²). The racial makeup of the city was 64.96% White, 0.10% African American, 0.03% Native American, 34.09% from other races, and 0.83% from two or more races. Hispanic or Latino of any race were 98.65% of the population.
There were 981 households out of which 60.2% had children under the age of 18 living with them, 74.0% were married couples living together, 14.5% had a female householder with no husband present, and 7.3% were non-families. 6.6% of all households were made up of individuals and 3.4% had someone living alone who was 65 years of age or older. The average household size was 4.08 and the average family size was 4.29.In the city, the population was spread out with 38.5% under the age of 18, 12.9% from 18 to 24, 27.4% from 25 to 44, 16.1% from 45 to 64, and 5.1% who were 65 years of age or older. The median age was 24 years. For every 100 females there were 96.2 males.
For every 100 females age 18 and over, there were 94.5 males.The median income for a household in the city was $17,743, and the median income for a family was $18,056. Males had a median income of $16,628 versus $12,670 for females. The per capita income for the city was $5,131. About 49.0% of families and 47.8% of the population were below the poverty line, including 52.2% of those under age 18 and 60.5% of those age 65 or over