Spokane River Centennial State Park Trail History

The 40-mile Spokane River Centennial State Park Trail weaves together rural, urban, and park landscapes filled with stories of land and people. The trail stretches through the Spokane River Valley, meandering from the Idaho/Washington state line to Riverside State Park.

The Forces of Plate Tectonics

370 million years ago, the west coast of North America was found in the vicinity of today’s trail. Around that time, a convergence of dense oceanic crust with the continental margin resulted in the denser slab sinking beneath the continent, a process called subduction, driven by convection from the Earth’s depths. In the heat of the planet’s interior, the old cold slab melted, and ascending fluids created an arc of volcanoes on the surface above. That process has continued, with variations, up to the present.

A major influence on the scenery along today’s trail occurred about 17 million years ago, as lava began oozing up through cracks in the earth near the present-day Washington-Oregon-Idaho border. This happened repeatedly, often with thousands of years passing between flows. In total, the lava flows—more than 300 of them—produced layers of basalt almost two miles thick that cover about 40% of present-day Washington, creating the distinctive layered bluffs and canyons on the western parts of the trail.

Ice Age Floods and the Spokane Valley Aquifer

In the final stages of the most recent ice age, masses of glacier ice repeatedly blocked meltwater drainage upstream from today’s Spokane Valley, creating huge bodies of impounded water in northern Washington, Idaho and Montana. When the ice dams melted or were breached by the sheer weight of water behind them, gigantic floods swept over the landscape. Dozens of times over thousands of years, ice dams formed and gave way, sending floods racing through. The floods scoured the land, carving cliffs and river channels deep into thick layers of basalt across the Columbia Plateau, and also deposited thick layers of gravel and cobbles, partially filling the valleys of northern Idaho and the Spokane River.

The mass of gravel and cobbles receives and stores water from precipitation, tributary streams, and seepage from lakes and rivers. The water stored underground makes up the Rathdrum Prairie-Spokane Valley Aquifer. Groundwater in the aquifer flows from north to south at a rate of about 50 feet per day. About 20-25% of the rain and snow that falls on the region directly recharges the aquifer.

Communities along the route of today’s Spokane River Centennial State Park Trail use well water drawn from the aquifer for homes, industries, and agriculture.

Indigenous Lands

The Spokane River Centennial State Park Trail meanders through the traditional territories of the region’s Indigenous people. The route lies within the territories of Sahaptian and Interior Salish Indigenous people whose present-day descendants include members of the Spokane Tribe of Indians and the Coeur d’Alene Tribe.

Ancestors of today’s tribal members traditionally followed a seasonal round throughout areas of central and eastern Washington, maximizing access to necessary resources by spending time in each area at the optimal time for harvesting the resources featured in each ecosystem.

All tribes utilized parts of the route traversed by today’s trail to reach important resources and connect with other people for trade and social gatherings. A regular point for crossing the river was located at Coyote Rocks, a stretch of the river with ice-age-flood-deposited boulders.

In 1852, Antoine Plante, a fur trapper who had previously worked for the Hudson’s Bay Company, settled in the vicinity of Coyote Rocks with his wife Mary (Flathead) and developed a ferry crossing at the site which was licensed by the Washington Territorial Legislature in 1860.

Dispossession and Land Disposal

Representatives of numerous Indigenous people with traditional territories in what is now central and eastern Washington negotiated and signed treaties with Territorial Governor Isaac I. Stevens at Walla Walla on June 9, 1855. The treaties were not ratified by the US Senate until 1859, and in the interim, the benefits promised by the treaties were not available to the tribes that had signed.

The discovery of gold in the Colville area resulted in numerous Euro-American prospectors entering onto unceded Indigenous land, sometimes coming into conflict with residents. A government agent sent to investigate the incidents, Andrew Bolon, was killed by a party of Indigenous warriors.

In response, the US Army unsuccessfully sent soldiers into the area to apprehend those involved, initiating what came to be known as the Yakama War. After several skirmishes and a widening of the conflict into the Puget Sound area, Colonel George Wright was ordered to “attack All the hostile Indians you meet, with vigor; make their punishment severe and persevere until the submission of all is complete.”

Armed with new, highly accurate rifles, Colonel Wright’s forces engaged the allied tribes at the Battle of Spokane Plains on September 5, 1858.

In the days following the battle, Colonel Wright ordered the destruction of the Indigenous people’s food stores and dwellings in the Spokane Valley, and over 800 Indigenous-owned horses were slaughtered at a place in the eastern part of the valley near Mile 3 on today’s trail. The atrocities culminated in the summary execution of some Indigenous leaders later in September.

The lands taken from Indigenous residents became federal public domain lands. The lands were surveyed by government surveyors over the next few decades following the pattern established by the Land Ordinance of 1785, with the land divided into one-square-mile (640 acres) units called “sections” grouped into 36-square-mile units called “townships.”

The land in the townships of the Spokane Valley was distributed by the US General Land Office to people that qualified to receive it under terms of land disposal laws passed by the US Congress. Antoine Plante, however, did not file a claim for the property he had lived on for many years.

Much of the land in the valley was granted to the Northern Pacific Railroad (NP) as a subsidy for the construction of rail lines into the Pacific Northwest. The tract occupied by Plante was included in the NP land grant, and he was forced to leave in 1878.

Eventually, the NP sold most of its granted lands, including the Plante home, to other private owners. Most of the riverbanks and uplands upstream of the city of Spokane were acquired by the Inland Empire Paper Company, which established a factory at Millwood in 1911, across the river from today’s Donkey Island Trailhead near Mile 13 on the Spokane River Centennial State Park Trail.

Much of the riverbanks and uplands downstream from the city were acquired by the state to become Riverside State Park.

The Rise of Spokane—Planning for Parks—World’s Fair

The city of Spokane (originally “Spokane Falls”) grew rapidly after Washington achieved statehood in 1889, drawing on natural resource extraction throughout the interior to power its growth.

Businessman Aubrey L. White was instrumental in lobbying Spokane’s leaders to plan and develop a system of parks in the city in the early 1900s, including some along the banks of the Spokane River. White emphasized in his conversations with leaders how important it was to reserve lands for park purposes while desirable tracts of land were still undeveloped and remained affordable investments for public acquisition. As a result of his efforts, the city commissioned the Olmstead Brothers landscape architecture firm to create a plan for parks and city voters approved a $1 million park bond measure on May 3, 1910.

The Olmstead Brothers’ report criticized the industrialization of Spokane Falls in the heart of the city and encouraged the eventual reclamation of the site for public recreation. When Spokane won a bid to host the 1974 World’s Fair, planners drew on those ideas to design a public focal point in the heart of the city by the falls. The environmental-protection-themed event jumpstarted reclamation of the area, and local boosters began to envision a recreational trail and green space running the length of the Spokane Valley, well beyond the city limits.

Making a Park

In 1984, the Spokane Valley Chamber of Commerce formed a Parks and Recreation Steering Committee to promote the idea to various local and state agencies. Local insurance salesman Denny Ashlock kept the vision alive even when proponents were called “communists and fools” for proposing a trail that he hoped would create better appreciation of the Spokane River.

In 1988, the Washington State Parks and Recreation Commission (WSPRC) executed a land trade with the Inland Empire Paper Company, trading over 3,000 acres of scattered tracts of state-owned land surrounding Mount Spokane State Park that lacked public access for a 500-acre strip of land on the Spokane River.

Planners hoped to complete the trail in time for the centennial of Washington’s statehood in 1989. A federal appropriation of $7.2 million for trail construction was secured and matched with local contributions, allowing a phased opening of the trail.

In 1990, the WSPRC voted unanimously to close a portion of the Aubrey L. White Parkway (built by the Civilian Conservation Corps during the Great Depression) within Riverside State Park to motor vehicle use, routing the Centennial Trail over that route within the park.

The same year, the bridge that carries the Spokane River Centennial State Park Trail over the Spokane River near the Coyote Rocks crossing used by Indigenous people for many centuries was completed. The bridge is named in honor of Denny Ashlock, who passed away in 1997.

The Spokane River Centennial State Park Trail remains a work in progress, as cooperating park managers from the WSPRC, Spokane County, the City of Spokane Valley, the City of Spokane and the volunteers of the Friends of the Centennial Trail continually work to improve the routing and maintenance of the trail. As a part of that ongoing process, the easternmost 14 miles of the trail were resurfaced in 2024 to provide a smooth walking, running and riding surface for the next 25 years.