Falls County is part of the Waco, Texas, metropolitan statistical area.

[4] The Brazos River valley served as hunting grounds for several tribes, including Wacos, Tawakonis, and Anadarkos.

From 1843 onward, the Tawakoni were part of treaties made by both the Republic of Texas and the United States.

[6][7][8] January 1839, Falls County had two brutal massacres by the Anadarkos, under chief José María,[9] at the homes of George Morgan and John Marlin.

Empresarios Sterling C. Robertson and Robert Leftwich received a grant from the Coahuila y Tejas legislature to settle 800 families.

[13] By contracting how many families each grantee could settle, the government sought to have some control over colonization.

[16] The settlement was deserted during the Runaway Scrape[17] of 1836, and reoccupied after the Battle of San Jacinto.

The county fared better during Reconstruction than most, perhaps due to its distance from areas subject to Union military occupation.

[23] Conrad Hilton built the Falls Hotel, with a tunnel to a mineral bath, to accommodate the business generated by the hot spring.

The Waco Division of the San Antonio and Aransas Pass Railway,[25] in 1886–1925, had multiple stops in Falls County.

The concrete, brick, and stone fifth and present-day courthouse, designed by architect Arthur E. Thomas,[28] was completed in 1939.

[36] The TDCJ also operates the William P. Hobby Unit, a prison for women located southwest of Marlin in unincorporated Falls County.