Wetumpka Crater

The Wetumpka Impact Crater is a buried and eroded impact structure in eastern Elmore County near Wetumpka [1]. About 83 million years ago an asteroid or comet roughly 1,250 feet (380 meters) across struck the area, then under shallow sea. The original crater was about 4.7 miles wide, and today only a crescent-shaped ridge survives, rising up to 300 feet above the surrounding river plains. Wetumpka was recognized in 2002 as the 157th known impact crater on Earth.

Ancient setting

When the impact happened, sea level was much higher, and the shallow northern Gulf of Mexico covered much of southern and central Alabama. The strike occurred about 15 miles offshore in water roughly 100 feet deep. The city’s name comes from a Creek word for “rumbling waters,” which fits an impact in seawater [1]. See Muscogee (Creek) People in Alabama.

Discovery

In 1969 geologists from the Geological Survey of Alabama, led by Thornton L. Neathery, first noted the structure, and in 1976 they proposed a meteor origin. In 1999 a team including Neathery and Auburn University geologist David T. King Jr. drilled 630 feet at the center. The core showed shock-deformed minerals, which form only in cosmic impacts and nuclear tests, and geochemical analysis found meteoritic elements including iridium, cobalt, nickel and chromium. The team published its findings in 2002 in Earth and Planetary Science Letters [1].

Effects

The energy released was about 175,000 times that of the Hiroshima bomb, and effects likely included a large earthquake, a tsunami, hurricane-force winds from an atmospheric blast and falling debris. Many organisms along the ancient shoreline were wiped out, though the event had no global consequences and is not linked to a mass extinction [1].

Today

The rim is hard crystalline rock, while the interior is softer sedimentary material. Bald Knob, the highest point of the rim, is visible from US 231 and Alabama 14. The city of Wetumpka holds annual lectures and public tours of the crater, and the Alabama Historical Commission installed a roadside marker in 2002 [1]. The Alabama River begins here at the Coosa-Tallapoosa confluence.

Location and size

The Wetumpka crater, east of downtown Wetumpka in Elmore County, is described as the only confirmed impact crater in Alabama. It is about 4.7 miles (7.6 km) across and dates to the Late Cretaceous, with age estimates of about 81, 85 or 80 to 83 million years depending on the source.[2]

Discovery and confirmation

Thornton L. Neathery found it in 1969-70 during regional geological mapping and published the first article in 1976. Impact origin was not conclusively shown until 1998, when David T. King Jr. and colleagues found shocked quartz in a core drilled near the center, and Auburn University researchers published supporting evidence in 2002.[2]

The impact

The estimated projectile was about 1,100 feet across and struck at an angle of 30 to 45 degrees from the northeast into a shallow sea about 300 to 400 feet deep. The crater retains its original impact rim and breccia.[2]

FAQs

How big was the Wetumpka impact? The object was about 1,250 feet across and the crater about 4.7 miles wide.

How was it confirmed? Core samples showed shock-deformed minerals and meteoritic elements.

Can I visit? The city holds annual lectures and public tours.

Sources

1. Encyclopedia of Alabama: Wetumpka Impact Crater
2. Wikipedia: Wetumpka crater

Editorially reviewed by Specialty Digest Editorial TeamLast reviewed November 10, 2026Researched and drafted with AI assistanceReport an issue