In 1859, the U.S. Army located a fort 12 miles southeast of the Hudson's Bay Company's trading hub.  It was also named, Fort Colville, but with a second "l" in it.  In the aftermath of the 1855-58 interior skirmishes the army fought with indigenous native nations who rose up to fight to protect their private lands from settler colonists not allowed in the June, 1855 Walla Walla Treaty--until the U.S. Senate approved the payments negotiated within its treaty for native nations' real estate.  [The U.S. Senate's approval took until 1859].
  This army fort's establishment was made to provide "protection" for the Upper Columbia's indigenous natives from their being overrun by gold-seeking prospectors coming there from across the world.  But it also was there to police the interior of the new international boundary as well as ex-im mineral and commercial trade activities, including those of Hudson's Bay Company.  As a consequence of the latter, the HBCo moved upriver, just north of the border and across from the mouth of the Pend d' Oreille River tributary confluence.  But HBCo had to await a post-Civil War settlement of its real estate before formally leaving its last U.S. land claim--the land at Fort Colvile. Pioneer retailers thus came to fill the commercial vacuum left by HBCo.