Editing Pacific Northwest (section)

===Subsequent land explorations===
{{unreferenced section|date=December 2022}}
The [[Willamette River]] was the first PNW inland waterway to be explored north–south during trapping expeditions carried out throughout the 1810s by the [[Pacific Fur Company]] soon acquired by the [[North West Company]] (NWC). During the 1820s, the upper Willamette, the [[Umpqua River|Umpqua]], the [[Rogue River (Oregon)|Rogue]], the [[Klamath River|Klamath]] were all reached still heading southward up toward the [[Sacramento River]] and [[California]] under the [[Hudson's Bay Company]] (HBC) having now itself acquired the NWC. The [[Siskiyou Trail]] was gradually being established by [[Alexander Roderick McLeod]] and [[Peter Skene Ogden]] leading related expeditions for the HBC.
 
Also during the 1820s, HBC explorations were carried out northward originating from the [[Columbia River]] [[Fort Astoria]] long renamed to Fort George. Simon Plamondon first ventured during the early 20s  into the [[Cowlitz River]] up to [[Cowlitz Prairie]]. By 1824, an expedition led by [[James McMillan (fur trader)|James McMillan]] was reaching [[Puget Sound]] via the [[Chehalis River (Washington)]] and a portage. The same expedition went on all the way to [[Boundary Bay]] and reached the [[Fraser River]] via the [[Nicomekl River|Nicomekl]] and the [[Salmon River (Langley)|Salmon]] linked via a portage. The lower Fraser was revisited 16 years after explorer [[Simon Fraser (explorer)|Simon Fraser]] (NWC) had first reached its mouth, although originating from northern present-day [[British Columbia]]. Puget Sound soon after would get reached via the Cowlitz and the Cowlitz Landing portage, but originating from new HBC headquarter [[Fort Vancouver]] located closer by, north of the Columbia.