The Harpeth River is one of the major streams of north-central Middle Tennessee and one of the major triubtaries of the Cumberland River.
The Harpeth rises in the westernmost part of Rutherford County, Tennessee, just to the east of the community of College Grove, in eastern Williamson County. The upper portion of the river has been contaminated to some extent by the operation of a lead smelting plant located near the Kirkland community which smelted recylcled automobile batteries from the 1950s until the 1990s.
The stream flows generally westerly into the county seat of Williamson County, Franklin, which has become an affluent suburb of Nashville since the 1960s. The Harpeth has been put under a great strain by the growth of Franklin and the surrounding area, as it is the source of the area's drinking water supply and also the main site of its sewage disposal. Reportedly the Harpeth was navigable by shallow-draft vessels as far upstream as Franklin in the 19th century during periods of high flow; this is hard to envision today.
At Franklin, the course of the river turns more northwesterly; a few miles northwest of Franklin is the mouth of one of the Harpeth's main tributaries, the West Harpeth, which drains much of the southern portion of Williamson County. Near this site is an attractive antebellum plantation home called, appropriately enough, Meeting of the Waters. The river in this area flows quite near the Natchez Trace (the original road of that name, not the modern Parkway named for it, which is several miles distant). The river shortly crosses into Davidson County and receives the flow of the Little Harpeth River, another important tributary. The stream flows near the unincorporated Nashville suburb of Bellevue and shortly after this flows into Cheatham County.
The course of the river in Chetham County is very meandering. A few miles into Cheatham County it is joined by the flow of another major tributary, the South Harpeth, which drains some of the southwestern portion of Davidson County, southeastern Chetham County, and a small portion of northwesternmost Williamson County. In Chetham County is a remarkable civil engineering feet of the early 19th century. At a place known as the "Narrows of the Harpeth", across from the "Mound Bottom", an area dotted with Native American ceremonial and burial monds, ironmaster Montgomery Bell built an iron mill, largely through the use of slave labor. At a seven mile (11 km) horseshoe bend, Bell's slaves under his direction cut a tunnel through apporoximately 200 yards (180 m) of solid rock, assisted only by black-powder blasting techniques, to build a diversion tunnel to power the mill, which Bell called "Pattison Forge" (often spelled, incorrectly, "Patterson") after his mother's maiden name. Bell was so pleased with this feat that he curtailed some of his other area operations and even built a home near the site. Today, the tunnel and some "slag" are about all that remains of the operation. The tunnel is the main attraction, along with the sheer bluffs at the eastern end of the bend, of Narrows of the Harpeth State Natural Area. The tunnel is a registered National Engineering Landmark.
From this historic site, the flow becomes generally more notherly, but still greatly meandering. The Harpeth soon forms the line between Dickson County and Cheatham County for the last part of its course. A few miles above the mouth are what are known as the Three Islands; the United States Army Corps of Engineers proposed siting a dam near this location on several occasions and even did some preliminary study toward one, but a favorable cost-benefit ratio could never be satisfactorily shown and the project was never built. Partially because of this fact, the lower portion of the Harpeth is very popular with canoeists and canoe outfitting businesses exist to rent canoes to them, which is a popular summertime activity with youth groups especially. The mouth of the Harpeth into the Cumberland is near the Ashland City, the Chetham County seat. Near the mouth is a bridge on Tennessee Highway 49 named in Montgomery Bell's honor. The mouth is just below the Cumberland's Harpeth Island, and is somewhat submerged by the backwaters of the Corps' Chetham Dam.
The Harpeth is Middle Tennessee's second longest unimpounded steam (the longest being the Buffalo). The origin of the name "Harpeth" is controversial. It is often cited in the area that it is named for the legendary outlaw brothers of the early 19th century in the area, the Harp Brothers, "Big Harp" and "Little Harp"; this is erroneous, as the name exists on maps and documents predating their fame. A late 18th century map, published in London, purportedly shows the steam as the "Fairpath"; there is some dissension about whether the name is of Native American origin or perhaps a corruption of the rather common English name "Harper". (There is no dispute about whether the title of the song Harper Valley P.T.A. by Tom T. Hall is derived from this stream indirectly; it is. Hall, long an area resident, says that the song's name derives from Harpeth Valley Elementary School in Davidson County near Bellevue, but he also states that the song was definitely not based on any occurrence there; rather that he liked the sound of it.)
The lower portion of the Harpeth is designated as a "scenic river" under the Tennessee Wild and Scenic Rivers Act.