Native Am. Indian Timeline 

(All dates are correct to the best of my knowledge, but obviously are subject to lots of  error)

4 billion years ago, Earth formed.
80-35 million years ago, Cascade Mts formed, Olympic Mts are islands out to sea.
34 million years ago, creation of Columbia Plateau,
34-10 million years ago, Floods of lava cover Columbia Basin, destroying Columbia River waterway.
40,000 years ago, First ash deposits from Mt St Helens.
10 - 20 thousand years ago, Washington Ice Age.
10,000 years ago, Kennewick man remains (first indians?)
1700, horses introduced to indians on Columbia plateau, buffalo now gone from plateau.
1741-1743, Russian Explorers trade for sea otter pelts in Alaska area.
1774, Juan Perez sights Olympic Mts.
1778, James Cook explores Coast of Washington/Canada.
1792, Robert Gray names Columbia River after his ship.
1800, Kamiakin's birth.
1807-11, David Thompson charts Columbia River
1810, Spokane House fur trading, Garry's father frequented the place.
1811, approx. Chief Garry Spokane Birth
1816, Advent of Photography
1817, approx. next to last Mt St Helens eruption dropping ash and darkening the day in Spokane.
1825, Forts Vancouver and Colville built on Columbia River.
1829, Birth of Chief Moses
1838, Tshimkian Mission established by Cushing Eells and Elkanah Walker.
1845, A. J. Splawn born, Author of Kamiakin: The Last Hero of the Yakimas; Major historian of the area.
1846, 49th parallel set as boundary between Canada/USA
1847, Cayuse attack Whitman Mission
1853,  Washington Territory created
1855,  Yakima Tribe Wars, and Walla Walla Treaty Council
1856,  Fort Simcoe established
1857,  Rise of Spokane Garry as notable chief
1858,  Steptoe War, led by Kamiakin
1858,  Indian Wars at Four Lakes, Horse Slaughter Camp, Hangman Creek hanging of Qualchan
1859,  Mullan road from Walla Walla to Fort Benton
1860,  Okanogan gold/silver discovery
1873,  Glover, the Father of Spokane
1875,  Approximate Death of Kamiakin
1877,  Nez Perce Wars, Joseph: "I will fight no more forever." Kamiakin Dies
1886,  Rich Mine development causes development of Spokane from shacks to brick bldgs 
1889,  Washington territory becomes the 42nd state, Spokane's Great Fire
1890,  Spokane's age of elegance due to mining riches flowing here
1892Chief Garry Spokane Death
1899Chief Moses Death
1917,  A. J. Splawn dies, Author of Kamiakin: The Last Hero of the Yakimas
1980,  Last Mt St Helens eruption dropping ash and darkening the daylight in Spokane