Tomball is a city in Harris County in the U.S. state of Texas, a part of the Houston metropolitan area. The population was 12,341 at the 2020 U.S. census. In 1907, the community of Peck was renamed Tomball for local congressman Thomas Henry Ball, who had a major role in the development of the Port of Houston.

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.