Centennial Trail State Park is a 40 mile paved trail, managed by Riverside State Park. The park consists of a paved trail meandering along the Spokane River and extending from Nine Mile Falls to the Idaho state line. The trail is punctuated with 42 historical and archaeological sites, most of which remain to be marked. This park consists of a 37-mile long, 12-foot wide paved trail extending from Nine Mile Falls near Spokane to the Idaho border. On the Idaho side, the trail continues on. The trail follows the Spokane River, and is marked by sites of historic and archaeological interest.

Environmental Features At mile marker 36, the visitor can explore fossil beds in the Deep Creek area of the trail. The Center of Northwest Anthropology at Washington State University conducted an archaeological survey at the site, uncovering evidence of life dating back 11,000 years. The study determined that civilizations past used the Spokane River for transportation, a food source, and a place of gathering.

The trail was dedicated and named the Centennial Trail in 1989, in commemoration of Washington state's 100th birthday that year.

The trail contains interpretive signs and 42 historical sites, most of which remain unmarked. Traveling west from the state line, one passes the site of the first bridge built over the Spokane River in 1864, and the site of the white settlement that preceded the city of Spokane. At milepost #2 sets the Horse Slaughter Camp monument. This is the site on which, in 1858, Colonel George Wright and his troops rounded up and killed 800 Indian horses to discourage future Indian uprisings. Down river from the Maribeau Park area is Plantes Ferry County Park. Here Isaac Stevens, the first territorial governor, met with the Upper and Middle Spokane in December, 1855. Also on this site, Antoine Plante operated a ferry from 1852 until 1864, when the Spokane bridge was built.

A Discover Pass is required for vehicle access to Washington state parks for day use. For more information about the Discover Pass and exemptions, please visit the Discover Pass web page.

This is a day-use park, but two campgrounds are available at nearby Riverside State Park. The Bowl and Pitcher area campground has 16 standard campsites, 16 utility hookup sites with electricity and water, one dump station and two restrooms, both with showers.

The Nine Mile Recreation Area has three tent sites and 21 RV sites of varying length.