The mountains were originally called "Sun-a-do" by the Duwamish Indians, while the first European to see them, the Spanish navigator Juan Perez named them "Sierra Nevada de Santa Rosalia", in 1774. But the English captain John Meares, seeing them in 1788, thought them beautiful enough for the gods to dwell there, and named them "Mount Olympus" after the one in Greece. Alternate proposals never caught on, and in 1864 the Seattle Weekly Gazette persuaded the government to make the present-day name official. Though readily visible from most parts of western Washington, the interior was almost entirely unexplored until the 1890s. Mount Olympus itself was not ascended until 1907, one of the first successes of The Mountaineers, which had been organized in Seattle just a few years earlier.
The Olympics have the form of a cluster of steep-sided peaks surrounded by heavily-forested foothills and incised by deep valleys.
The climax forests consist of Sitka spruce and western hemlock. Douglas fir occurs in groves. Other types of firs may be seen also. Clearings in the forest quickly become covered with vine maple, slide alder, and devil's club, making cross-country travel most challenging.
Another consequence of the high precipitation is the large number of snowfields and glaciers, reaching down to 1,500 m (5,000 ft) above sea level.