The construction of the Virginia and Coastal Railroad and the Atlantic Coast Line through St. Pauls helped establish the community as a leading producer of textiles. Three cotton mills were constructed in the early part of the 20th century. The mills experienced periods of success and failure before coming under control of the Burlington Mills Corporation in 1943. Nearly all the mills closed in the 1990s as the textile industry moved from the American South to Latin America and Southeast Asia.
According to the United States Census Bureau, the town has a total area of 1.3 square miles (3.4 km²), all of it land.
29.8% of households had children under the age of 18 living with them, 41.9% were married couples living together, 17.5% had a female householder with no husband present, and 33.5% were non-families. 30.8% of all households were made up of individuals and 14.7% had someone living alone who was 65 years of age or older. The average household size was 2.49 people and the average family size was 3.02 members.
The median income for a household in the town was $22,347, and the median income for a family was $27,708. Males had a median income of $27,218 versus $20,750 for females. The per capita income for the town was $12,520. About 17.2% of families and 22.8% of the population were below the poverty line, including 26.4% of those under age 18 and 24.9% of those age 65 or over.
The town has an elementary school, a middle school, and a high school, all named after St. Pauls. The population was spread out with 25.8% under the age of 18, 10.7% from 18 to 24, 28.1% from 25 to 44, 21.8% from 45 to 64, and 13.7% who were 65 years of age or older. The median age was 35 years. There were 94.8 males for every 100 females, and 89.7 males for every 100 females age 18 and over.