became Grimes County began in the 1820s, when it was part of Mexico. Early settlers were primarily from the South, especially Alabama, and many brought enslaved African Americans with them to work the land. The first cotton gin in Texas was built by Jared E. Groce, who arrived with 90 slaves and developed a cotton plantation near today's Hempstead, Texas.

Texas achieved its independence in 1836, and settlers arrived in greater numbers from the United States.