Spring is a census-designated place (CDP) within the extraterritorial jurisdiction of Houston in Harris County, Texas, United States, part of the Houston–The Woodlands–Sugar Land metropolitan area. The population was 62,559 at the 2020 census. While the name "Spring" is popularly applied to a large area of northern Harris County and a smaller area of southern Montgomery County, the original town of Spring, now known as Old Town Spring, is located at the intersection of Spring-Cypress and Hardy roads and encompasses perhaps 1 square kilometer (0.39 sq mi).

Harris County is a county located in the U.S. state of Texas; as of the 2020 census, the population was 4,731,145, making it the most populous county in Texas and the third-most populous county in the United States. Its county seat is Houston, the most populous city in Texas and fourth-most populous city in the United States. The county was founded in 1836 and organized in 1837. It is named for John Richardson Harris, who founded the town of Harrisburg on Buffalo Bayou in 1826. According to the July 2022 census estimate, Harris County's population has shifted to 4,780,913 comprising over 16% of Texas's population. Harris County is included in the nine-county Houston–The Woodlands–Sugar Land metropolitan statistical area, which is the fifth-most populous metropolitan area in the United States.