The Mission-Aransas National Estuarine Research Reserve is a large contiguous complex of wetland, terrestrial, and marine environments on the Texas Coastal Bend in the United States. Named for the two major rivers that flow into the area, the reserve contains public and private lands and waters. The land is primarily coastal prairie with unique oak motte habitats. The wetlands include riparian habitat, freshwater marshes, and saltwater marshes. Within the water areas, the bays are large, open, and include extensive tidal flats, seagrass meadows, mangroves, and oyster reefs. These unique and diverse estuarine habitats in the western Gulf of Mexico support a host of endangered and threatened species including the endangered whooping crane.