Elusive 19th century Alaskan fort located using radar tech

Researchers from Cornell University and the National Park Service have pinpointed and confirmed the location of the remnants of a wooden fort in Alaska—the Tlingit people's last physical bulwark against Russian colonization forces in 1804—by using geophysical imaging techniques and ground-penetrating radar.

The fort was the last physical barrier to fall before Russia's six-decade occupation of Alaska, which ended when the United States purchased Alaska in 1867 for $7 million.

The Tlingit built what they called Shiskinoow—the "sapling fort"—on a peninsula in modern-day Sitka, Alaska, where the mouth of Kasda Heen (Indian River) meets Sitka Sound at the Sitka National Historical Park.

"The fort's definitive physical location had eluded investigators for a century," said co-author Thomas Urban, research scientist at Cornell. "Previous archaeological digs had found some suggestive clues, but they never really found conclusive evidence that tied these clues together."

To find Shiskinoow, Urban created a grid to see if the electromagnetic induction methods could spot the potential outline of the fort and then created a small grid for dragging the ground-penetrating radar. Urban's modern tools picked up the fort's unusual perimeter shape.

"We believe this survey has yielded the only convincing, multi-method evidence to date for the location of the sapling fort, which is a significant locus in New World colonial history and an important cultural symbol of Tlingit resistance to colonization," Urban said.

In 1799, Russia sent a small army to take over Alaska in order to develop the fur trade, but the Tlingit successfully expelled them in 1802. Expecting the Russians to return, the Tlingit built a wooden fort over two years—the trapezoidal-shaped Shiskinoow. The Tlingit armed it with guns, cannons and gunpowder obtained from British American traders.

When the Russians returned in 1804, the Tlingit held them off for five days, but suffered a setback when a gunpowder supply being carried to the fort from storage across Sitka Sound blew up in a canoe. The Tlingit clans escaped Shiskinoow by night across Shee (Baranov Island) to Halibut Man Fort and the Russians then established a trading post at what is now Sitka.

"A large-scale survey was necessary to convincingly rule out alternative locations for this historically and culturally significant structure," said co-author Brinnen Carter of the National Parks Service.