The Washington Chapter was first chartered on November 22, 1997, and exists as an educational, non-profit group to encourage and support this stimulation and advancement of public knowledge and awareness of the historical, social and cultural significance and heritage of the Lewis and Clark Trail within Washington state.

It is one of more than 30 chapters of the Lewis and Clark Trail Alliance. The mission of the LCTA is to stimulate appreciation of the Lewis and Clark Expedition’s contribution to America’s heritage and to support education, research, development and preservation of the Lewis and Clark experience.