One national park river is widely regarded as the oldest river in North America, formed an estimated 260 million to 325 million years ago — although not all scientists agree the claim is true.

Rivers are constantly flowing and changing, but a few of the paths they carve into the Earth are as old as the Nile. And sometimes even older.

Scientists look at various geologic clues to help determine the age of a river, including how old the valley surrounding it is, how deep the water cuts into the riverbed, and the age of the sediments carried by the river. Researchers also look at the number of tributaries in a watershed — older rivers tend to have more of them — and the size of “meanders” — those twists, bows and curves in the water’s path that grow larger over centuries of erosion.

Some of the oldest rivers in the world include Australia’s Finke River and Western Europe’s Meuse. In North America, the New River, a Wild and Scenic River with 53 miles designated as the New River Gorge National River, is generally regarded as the most ancient, along with the Kanawha and French Broad Rivers. Although there is much debate on the subject, these three rivers together comprise a system of waterways that has been around for so long, it could well predate the continent as we know it.

The New River flows for 320 miles from the Blue Ridge Mountains of North Carolina northwest into Virginia and West Virginia, where it eventually connects with the Kanawha River. The river system is contained within basins in the Appalachian Mountains, and some scientists believe it is older than these mountains and that the water rose with them as they formed.

The Appalachians are themselves considered among the oldest mountains in the world. According to the U.S. Geological Survey, the rocks at the core of the mountains formed more than a billion years ago, and strong evidence suggests that tectonic collisions began folding the rock layers some 480 million to 440 million years ago. Around 300 million to 270 million years ago, the continents now known as Africa and North America collided with each other, leading to the creation of the supercontinent Pangea and pushing large masses of rock upward, forming the mountains and perhaps lifting the river system with them.

Determining the age of these geologic features is not a simple task, however, and not all scientists agree. Some believe that the original mountains that formed during the tectonic collisions on Pangea have completely eroded, and the Appalachian Mountains are the result of more recent tectonic shifts that uplifted newer formations along similar faults where the older mountains once stood. This could suggest that the New River is as young as 65 million years old. Research examining the erosion rate of the gorge would suggest an even younger age, since the canyon is not nearly as deep as those of other really old rivers; thus, some evidence suggests the river could be as young as 3 million years old — a mere baby in river years. Although the people who tout the river’s many great tourism opportunities like to reassert the idea that the river has been around for a very long time, the truth is that geologists haven’t yet determined the age with any level of precision — and all of it happened well before any person was there to create a record or even a legend about it.

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All of this begs the question, however: If the river could be exceptionally old, why the heck is it called the New River? This, too, is a mystery. One theory implicates two colonists, Thomas Batts and Robert Fallam, who explored the area in 1671. When they came across the river and didn’t recognize it, the story goes, they listed it as “new” on their map, and their notation was included in the official record and all subsequent maps to come. While we can’t verify whether this actually happened, stranger stories on the origins of park names exist.

Learn more about the present-day river and where to paddle, hike, bike and fish along its scenic waters by visiting the National Park Service’s New River Gorge National River website.

Nicolas Brulliard contributed to this story.