As of the census of 2000, there were 5,571 people, 2,120 households, and 1,500 families residing in the city. The population density was 560.1 people per square mile (216.2/km²). There were 2,789 housing units at an average density of 233.3/sq mi (90.0/km²). The racial makeup of the city was 81.60% White, 2.21% African American, 6.53% Native American, 0.29% Asian, 4.51% from other races, and 4.86% from two or more races. Hispanic or Latino of any race were 10.09% of the population.
There were 2,120 households out of which 33.9% had children under the age of 18 living with them, 54.1% were married couples living together, 13.0% had a female householder with no husband present, and 29.2% were non-families. 26.2% of all households were made up of individuals and 13.0% had someone living alone who was 65 years of age or older. The average household size was 2.54 and the average family size was 3.06.
In the city the population was spread out with 26.9% under the age of 18, 8.6% from 18 to 24, 28.6% from 25 to 44, 20.5% from 45 to 64, and 15.5% who were 65 years of age or older. The median age was 36 years. For every 100 females there were 94.0 males. For every 100 females age 18 and over, there were 89.7 males.
The median income for a household in the city was $33,283, and the median income for a family was $36,128. Males had a median income of $25,494 versus $18,919 for females. The per capita income for the city was $15,261. About 12.5% of families and 14.4% of the population were below the poverty line, including 19.9% of those under age 18 and 7.5% of those age 65 or over.
Purcell's Amtrak station is located at the lower level of the hill at east Main Street, and has daily rail service to Oklahoma City, Fort Worth, Norman and Ardmore. Interstate 35 runs north–south on the west edge of Purcell. The town is also served by U.S. Highway 77, State Highway 39, and State Highway 74. In addition, ODOT maintains State Highway 77C in downtown Purcell, a route which is not marked.