It flows generally north through the Pasayten Wilderness and across the international boundary.

Rock Creek also joins here, which makes the name "Three Forks" very appealing to not only the three way confluence, but to the nearby cabin.

The East Fork Pasayten River originates at Dollar Watch Pass and flows west, picking up the outlet stream from Big Hidden Lake just over halfway to its eventual meeting with the mainstream of the Pasayten just upstream from the Canada/United States border.

The Pasayten, prior to crossing the border, is joined by the East Fork.

The river, after crossing the border, continues to flow north.