The Bumping River is a tributary of the Naches River, in Washington in the United States. It flows down the east side of the Cascade Range, through Wenatchee National Forest and the William O. Douglas Wilderness. From its source at Fish Lake near Crag Mountain, it flows northeast to Bumping Lake, a natural lake enlarged and regulated by Bumping Lake Dam. Below the dam, the Bumping River continues flowing northeast. It is joined by the American River, its main tributary, a few miles above its mouth where it joins the Little Naches River to form the Naches River.