It flows generally southeast from Dawson County through Ballinger, Marble Falls, Lago Vista, Austin, Bastrop, Smithville, La Grange, Columbus, Wharton, and Bay City, before emptying into the Gulf of Mexico at Matagorda Bay.

[6] The Colorado River originates south of Lubbock, on the Llano Estacado near Lamesa.

It flows generally southeast out of the Llano Estacado and through the Texas Hill Country, then through several reservoirs including Lake J.B. Thomas, E.V.

In 1757, Spanish Texas attempted to establish an outlying Catholic mission (Mission Santa Cruz de San Sabá) on the San Saba River, near its confluence with the Colorado River.

[9] The river is an important source of water for farming, cities, and electrical power production.

In addition to power plants operating on each of the major lakes, waters of the Colorado are used for cooling the South Texas Nuclear Project near Bay City.