County Origins
Fort Bend County was founded in 1837 and named for a bend in the Brazos River
Fort Bend County gets its name from a small cabin settlement built near a sharp curve in the Brazos River in the 1820s.
Stephen F. Austin's settlers arrived in the early 1820s near a deep bend in the Brazos River. They built a two-room cabin called Fort Settlement, also known as Fort Bend. The county took that name when Texas lawmakers created it on December 29, 1837.
Richmond became the county seat on January 13, 1838. The Brazos River was the county's economic lifeline for decades. Steamboats carried cotton and sugar downriver to Galveston and beyond.
The county covers 869 square miles of coastal plain in southeastern Texas. The Handbook of Texas at tshaonline.org has a detailed entry on Fort Bend County's early history.
Source to confirm: Handbook of Texas – Fort Bend County