DALLAS, TX.- The only known document in private hands signed by both legendary American explorers Meriwether Lewis and William Clark, the men who opened up the West for America after the historic Louisiana Purchase of 1803, is expected to bring $100,000+ in Heritage Auctions’ June 10 Legends of the Wild West Signature® Auction.

In July, 1803, the United States – at the price of four cents an acre (totaling $15 million) – purchased 828,000 square miles of land from France. The Louisiana Purchase was arguably the most important land deal of the 19th century, doubling the size of the United States and giving it control of the important port city of New Orleans.

“Considering how the names Lewis and Clark are linked in the popular mind, it’s nothing short of amazing that this should be the only surviving document bearing both their signatures that exists in private hands,” said Tom Slater, Director of Americana Auctions at Heritage, “but that is indeed the case. Careful research confirms the Library of Congress doesn’t have anything, though there are possibly one or two land grants signed by both held in other institutional collections. It’s almost impossible to overstate the significance of this offering. Here’s a case where immense historical significance, profound human interest and extreme rarity come together to form a truly museum-quality treasure.”

Shortly after the Louisiana Purchase, Thomas Jefferson appointed Lewis and Clark to lead the 33-man Corps of Discovery on an exploration of the territory, which would take 2-1/2 years and produce more than 140 different maps, document nearly 50 different Indian tribes and record 300 previously unknown (at least to European Americans) species of plants and animals. After reaching the Pacific Ocean, the group turned back eastward and arrived back in St. Louis on Sept. 23, 1806. In 1807, President Jefferson appointed Meriwether Lewis governor of the Territory of Upper Louisiana with William Clark as an agent of Indian affairs as well as brigadier general of the militia of the territory. Meriwether Lewis signs this land indenture to prominent fur trader Pierre Chouteau (named in the document as Peter) as governor, six weeks before his death. William Clark and William C. Carr sign as witnesses.

Meriwether would die of a gunshot to the head and chest just six weeks after the signing of this document and, 200 years later, his death remains a mystery. He died en route to Washington, D.C. to take care of some financial business and explain his failures as governor. On the morning of Oct. 11, 1809, Lewis met his end at Grinder's Stand, a tavern located some 70 miles southwest of Nashville, Tennessee. It is generally accepted by scholars (and at the time by Thomas Jefferson and William Clark) that he committed suicide, but his family insisted that he was murdered.

The death of Lewis fell so near to the signing of this document that Carr, an original witness to the signing, was called upon a second time to attest to the document's legality. The document was notarized on the verso on Jan. 5, 1810, attesting to the veracity of the indenture.

“Auction records dating back to the 1970s fail to disclose another example of a document signed by both men, let alone one of such an historic nature,” said Slater. “As such, its significance and romantic appeal to institutional and private collectors alike is immense.”