Trinity River National Wildlife Refuge was established on January 4, 1994, with an initial purchase of . Since that time, the refuge has acquired additional acreage which now totals . The primary purpose of establishing this refuge is to protect a portion of the bottomland hardwood forest ecosystem along the Trinity River located in southeastern Texas. The refuge, which is a remnant of what was once a much larger natural area is a broad flat floodplain made up of numerous sloughs, oxbow lakes, artesian wells, and tributaries.