Brazos Bend is on the comparatively flat Texas Gulf Coastal Plain and falls within the Coastal Prairie vegetation region. Most of the park land is in the Brazos River floodplain, but there are areas of flat uplands typical of the coastal prairies.
The Brazos River bottomland and portions of Big Creek support a mixed hardwood vegetation community that includes pecan, elm, sugar hackberry, various species of oaks, and numerous species of shrubs and vines. Gallery forests along the river, creek banks and bayous are dominated by sycamore, cottonwood and black willow. The old meander escarpment of the Brazos River is characterized by magnificent moss-covered and vine-draped live oak woodlands. The flat uplands support tallgrass prairie, and the numerous swales and depressions become ponds during periods of heavy rainfall.
In addition to the Brazos River, the major water course is Big Creek, which meanders diagonally across the park and is associated with sloughs, bayous and cutoff meanders called oxbows. Two of these meanders form natural oxbow lakes, and two other oxbows are manmade by the channeling of Big Creek. Other lakes, such as Elm and 40-Acre, have been created by levees, dissecting the main channel of the ancient Brazos River. Pilant Lake, a shallow, freshwater marsh, is shared by the park and private landowners.
Wildlife is diverse and abundant. The white-tailed deer is the largest of more than 25 different species of mammals present, which also include bobcats, coyotes, raccoons, gray and red foxes, river otters, feral hogs and several species of rodents. Approximately 21 species of reptiles and amphibians have been recorded, and the smaller turtles, lizards, snakes and frogs are overshadowed in general interest by the American alligator, which is present mainly in the wetland areas of Elm, 40-Acre and Pilant lakes. (Feeding and harassing wildlife is prohibited.) Birds of 290 species have been sighted in and around the park. The diverse habitat is a haven for migratory waterfowl, a variety of shorebirds, wading birds, songbirds and raptors. Brazos Bend is a “must” on your coastal birding tour. (Bird feeders are allowed.)