It flows roughly parallel to the Idaho border for approximately 50 miles (80 km), through the Colville National Forest, past Tiger and Metaline Falls.

For example, in Stewart Holbrook's book The Columbia, he repeatedly refers to the Pend Oreille River as the Clark Fork.

Much of the Pend Oreille valley consists of relatively ancient metamorphic rock, uplifted over 500 million years ago from the former floor of the Precambrian sea that covered the region during that period.

About 200 million years ago, increased tectonic activity caused the uplift of the Idaho Batholith, a portion of which cooled and eroded to become the present main body of the Bitterroot Range, a major physiographic feature of the watershed which sweeps from northwest to southeast along the entire Clark Fork valley (and the border of Idaho and Montana), by about 70 million years ago.

This time period is generally accepted as when the entire Rocky Mountains system was formed, although age of the rocks varies with location.

Rather, it is now thought that the water completely breached the western divide of the Pend Oreille River valley and rushed out towards the direction of Spokane.

[9] Native people who lived along the river included the Pend d'Oreilles and Kalispel (considered as a single tribe by the Bureau of Indian Affairs).

Archaeological evidence suggests that people lived in the region as early as the end of the last ice age, about 11,000-12,000 years ago.

Afterwards he proceeded to establish trading posts throughout the region, including Kullyspell House on the north shore of Lake Pend Oreille.

These newcomers did not strike good relations with the Native Americans of the area, and diseases such as smallpox wiped out many indigenous (this happened with many other tribes across North and Middle America as they were not used to such a sickness).

After numerous wars and treaties, much of the land in the Pend Oreille basin especially the upper Clark Fork area had been ceded to the settlers.

In the late 1850s, a major influx of non-indigenous peoples occurred when gold was discovered near Metaline Falls on the Pend Oreille River.

In the 19th century, logging was the other major industry of the Pend Oreille River area and attracted hundreds to thousands of men to the region, many of them Scandinavian.

(Since it flows north, they had to tow the logs south, against the current, to ship it a shorter distance to the lumber mills and factories lower in the Columbia Basin.)

After the Idaho & Washington Northern Railroad was built in the area, steamboat commerce faded and the logs were transported by rail.

The little arable land that did exist was mostly within the river's floodplain, and in many places there was only a narrow strip of flat ground that would soon run against vertical cliffs or dense forests with rocky soil.

The smaller Albeni Falls Dam regulates the level of Lake Pend Oreille to provide some flood control during the summer and increased flows during dry winters.

Numerous dams upstream along the Clark Fork (Cabinet Gorge, Noxon Rapids and Thompson Falls) and Flathead (SKQ/Flathead Lake and Hungry Horse) also generate power and to a lesser extent regulate the inflows to Lake Pend Oreille and the Pend Oreille River.

In the 1920s, there was a proposal to divert the Pend Oreille through a 60 miles (97 km) gravity canal to irrigate the Grand Coulee and surrounding lands in eastern Washington as part of the tentative Columbia Basin Project.

This mitigation funding came in the form of removing the 50 foot (15 m) high ‘Mill Pond Dam’ on Sullivan Creek just upstream of the town of Metaline Falls.

Mill Pond Dam was removed in the summer of 2017 and the project finished in 2018 with stream and bank stabilization and native tree plantings.