The Buffalo River of Tennessee is the longest unimpounded river in Middle Tennessee, flowing through the southern and western portions of that region. It is the largest tributary of the Duck River and is a major stream used for canoeing, especially in its middle section.

The Buffalo rises in northern Lawrence County. Both the North and South Forks are crossed by U.S. Highway 43, the North Fork several times as it parallels that highway for about three miles (five km). The confluence of these two forks about a mile west of that highway is considered to be the head of the Buffalo. After the confluence, the Buffalo trends basically northwest for several miles, crossing into Lewis County, where it is crossed by the Natchez Trace Parkway. The confluence with the Little Buffalo River is in Lewis County as well, along with that of several other, more minor tributaries. The stream is paralled for a distance, and then crossed by, Tennessee Highway 99 while flowing through the broad Texas Bottoms. In Lewis County, although meandering, the course of the stream is basically westward. Entering into northern Wayne County, the stream receives several more tributaries, most notably the Green River.

A few miles below the mouth of the Green River near the community of Flatwoods, the Buffalo is bridged by Tennessee Highway 13 and then turns to run a basically northerly course for the balance of its flow. It also crosses into Perry County near here. The only towns of any size along the Buffalo, Linden and Lobelville, are located in Perry County. The eastern portion of Perry County is entirely drained by the Buffalo, the western portion by the Tennessee River itself. The Buffalo River is regarded by the residents as a defining physical feature, probably the defining physical feature, of the county. Canoeing float trips make a considerable contribution to the area's economy, which is fairly depressed compared to that of the state as a whole due in large to the general remoteness of the area. The Boy Scouts of America maintain a canoe base along the Buffalo in southern Perry County. The terrain in this area is of long ridges with fairly steep sides and deeply eroded hollows into those ridges, with the river itself in a wide flood plain of "bottom land". The predominant geology of the area is that of Paleozoic limestones; much of the diffential erosion leading to the terrain features is a result of the presence of large portions of chert, some of which bears small quantities of the iron-contaning mineral hematite or other oxides of iron, and differences in depostion and mineralization of the various types of limestone in the area. The sizable tributary streams mostly flow out of fairly narrow hollows into the Buffalo; only the largest ones have true stream valleys of their own. Part of the course of the Buffalo is designated as a "State Scenic River" under the Tennessee Wild and Scenic Rivers Act.

The Buffalo is rich in aquatic life. Fishing it through passive methods such as limb and trot lines is traditional. There are many catfish and other nongame fish such as drum. The largest aquatic animal often found in the Buffalo is the alligator snapping turtle; which is in fact often caught (unintenionally for the most part) on trot and limb lines. These can easily weigh 50 pounds (23 kg) or more.

For most of its flow through Perry County, the Buffalo is roughly paralled by Tennessee Highway 13. Shortly after crossing into Humphreys County, it is bridged by Interstate 40. A few miles north of this is its confluence with the Duck.