Clark's Mountain is a 355-metre summit in Ecola State Park on the Oregon coast near Tillamook Head. Named for William Clark of the Lewis and Clark Expedition, it is linked to the party's passage here in 1805 and 1806, when Meriwether Lewis and Clark described the surrounding headland and Clark crossed the summit, praising the view. Although Lewis once called it "Clark's Mountain and Point of View," that name fell out of use as the promontory became known as Tillamook Head. Its present official name was adopted in 2001 and 2002, and it is notable for retaining the possessive apostrophe in federal usage.