Knoxville is a city in Johnson County, Arkansas, United States. The population was 731 at the 2010 census.Knoxville is located at 35°22′59″N 93°21′57″W / 35.38306°N 93.36583°W / 35.38306; -93.36583.According to the United States Census Bureau, the city has a total area of 2.2 square miles, all of it land.As of the census of 2000, there were 511 people, 194 households, and 138 families residing in the city. The population density was 230.3 people per square mile. There were 210 housing units at an average density of 94.7/sq mi. The racial makeup of the city was 95.89% White, 1.57% Native American, 0.20% Asian, 1.37% from other races, and 0.98% from two or more races. 4.11% of the population were Hispanic or Latino of any race.There were 194 households out of which 34.5% had children under the age of 18 living with them, 59.8% were married couples living together, 8.8% had a female householder with no husband present, and 28.4% were non-families. 22.