Mamachatpam

Mamachatpam is the self-name of the Lower Yakama, the largest of the five or six Sahaptin-speaking bands that outsiders gathered under the name Yakama. Their villages held the lower Yakima River east of the Cascade Range, and they were also called Pa'kiut'lĕma, people of the gap, after their main village in the Union Gap.

Their upriver cousins were the Kittitas or Upper Yakama, and the related Wanapum kept the Columbia about Priest Rapids, where they cut more than three hundred petroglyphs into the basalt cliffs. All spoke Ichishkíin, a Sahaptin language of the Plateau Penutian family, and lived on Columbia salmon, camas roots and game.

In 1805 the Wanapum chief Cutssahnem welcomed the Lewis and Clark Expedition with food and dancing. In 1805 or 1806 the corps met the Yakama bands themselves at the river confluences of their country.