Texas contains thousands of bodies of water typically referred to as lakes. Nearly all of these are man-made reservoirs created by damming rivers, which serve as a source of water supply and flood control for the state. Determining the single “biggest” lake requires establishing a consistent standard of measurement, as rankings change significantly based on whether the metric is total surface area, maximum water volume, or depth. For the purpose of establishing a general title holder, surface area is the most common and widely accepted metric.
The Title Holder: Texas’ Largest Lake by Surface Area
The largest body of water straddling the Texas border, and thus the state’s largest lake by surface area, is the Toledo Bend Reservoir. This immense man-made lake spans an estimated 185,000 surface acres, which is roughly equivalent to 289 square miles of water. Located in East Texas, the reservoir was created in the late 1960s by impounding the Sabine River, with the border between Texas and Louisiana running directly through its center.
Its size makes it the largest man-made body of water in the Southern United States and the fifth largest reservoir by surface area in the nation. The reservoir’s construction was a joint effort between the two bordering states, primarily serving to generate hydroelectric power and provide a stable water supply for both Texas and Louisiana communities. With over 1,200 miles of shoreline, the reservoir also functions as a significant recreational destination, known for fishing, boating, and various water sports.
Beyond Surface Area: Volume, Depth, and Runner-Up Reservoirs
While surface area provides a simple measure of size, the ranking of Texas’s largest lakes becomes more complex when considering other physical attributes. The total volume of water a reservoir can hold, measured in acre-feet, is another common metric used to gauge capacity. Toledo Bend Reservoir is also the largest by volume, with a capacity of approximately 4.47 million acre-feet. Other reservoirs, such as Falcon International Reservoir on the Rio Grande, also contain a substantial capacity, approaching three million acre-feet.
The largest lake located entirely within the Texas border is the Sam Rayburn Reservoir, situated north of Beaumont in East Texas. This reservoir covers approximately 114,500 surface acres, making it the second-largest overall in the state. Other major reservoirs rounding out the largest bodies of water include Lake Livingston (93,000 acres) and Lake Texoma (89,000 acres), which straddles the Oklahoma border.
The state also contains some natural lakes, though they are significantly smaller than the large man-made reservoirs. Caddo Lake, located on the Texas-Louisiana border, is often cited as the largest natural lake in the state, covering an area between 25,000 and 27,000 acres. Its unique ecosystem, characterized by flooded cypress forests, distinguishes it from the large, deep, and open-water reservoirs that dominate the state’s rankings.