The Grand Chapter of Royal Arch Masons of Idaho was Organized on 16 June, 1908, as proclaimed by the General Grand High Priest of the General Grand Chapter of Royal Arch Masons of the United States of America with the following Chapters:

Idaho City Chapter #1, Idaho City                  Cyrus Chapter #2, Silver City

Boise Chapter #3, Boise                                Lewiston Chapter #4, Lewiston

Pocatello Chapter #6, Pocatello                      Moscow Chapter #7, Moscow 

Payette Chapter #8, Payette                          Wallace Chapter #9, Wallace

Idaho Falls Chapter #10, Idaho Falls               Weiser Chapter #11, Weiser

Coeur d'Alene Chapter #12, Coeur d'Alene      Grangeville Chapter #13 UD, Grangeville

Salmon Chapter #14 UD, Salmon

The Grand Chapter now consists of nine Chapters.