American history between the War of Independence and the War of 1812 is an empty period to most people today. But the Lewis and Clark expedition was big news back then, and westering Americans in the ensuing generations had good reason to remember at least some of the major places and events along the expedition's route.
One of the first writers to devote special attention to the question of Fort Clatsop's post-history was Olin D. Wheeler, who visited the site with Coboway's grandson, Silas B. Smith, in 1900, and wrote briefly of it in his historical travelogue, The Trail of Lewis and Clark, 1804-1904.
Although Smith's mother claimed her father's people used the fort as a hunting camp for a decade or so, Gabriel Franchére, who arrived on the ship Tonquin with John Jacob Astor's Pacific Fur Company in 1811, visited the site and saw only piles of rough, unhewn logs overgrown with vines. Seven years after the Corps left it, Alexander Henry, of the Hudson's Bay Company, saw 25-foot trees growing among the ruins. In the early 1820s, the young ornithologist John Townsend, who accompanied Nathaniel Wyeth on his Columbia River expedition, found a couple of peace medals in the vicinity.
Beginning shortly before 1850 a succession of settlers cleared the land and set about farming, and later in the century logging and pottery businesses operated at or near the site. Meanwhile, a thin but resilient thread of personal attachment, legend, and reverence for its significance kept the hallowed place in mind for nearly a century.
The Oregon Historical Society acquired the site in 1901, erected a commemorative marker in 1912, and installed a bronze plaque there in 1928. The reconstruction visitors see now was built in 1955, and in 1958 the replica and some surrounding land was acquired by the National Park Service as a National Memorial. The first visitor center was built in 1963, and expanded into the present facility in 1991.
In an effort to reconcile the contradictions inherent in Fort Clatsop's oral history, and to fix its precise location once and for all, archaeological studies were undertaken in 1948 and 1961, but were inconclusive. In 1996 a third exploration, employing the latest research technologies, was carried out but was similarly fruitless.