Today, half of Texas's expanding population, including the cities of Dallas–Fort Worth and Houston, depends on the Trinity River, a river that has shaped the state's politics, economy, and environment for centuries. From the prairies of North Texas to the Gulf of Mexico, the Trinity established Native nations, foiled Spanish and French imperialism, stood at the center of the Texas plantation system, and fueled the growth of the state's largest cities.

In the first history of this vital river, historian Scot McFarlane illuminates how the Trinity has defined Texas history. Its floods enriched the soil and destroyed crops, its channel served as both a route and barrier to freedom, and its once-polluted waters now sustain a significant portion of the state. McFarlane's captivating narrative brims with stories of the people who called the Trinity home over the centuries: the Comanche, steamboat pilots, enslaved and freed people, sharecroppers, inmates, and millions of urban residents. The result is a fresh perspective on economic development, slavery, and the environment—revealing the Trinity not as a backdrop to Texas history but as a force that shaped it.

Scot McFarlane is a river historian and founder of the Oxbow History Company.