|The International Temple, Supreme Assembly, Order of the Rainbow for Girls is eligible for the National Register of Historic Places under Criterion A in the area of social history as the world headquarters for the Order of the Rainbow for Girls and Criterion C in the area of architecture as an excellent example of mid-twentieth-century, Modeme architecture in McAlester, Oklahoma and as the international temple for the Order of the Rainbow for Girls. The International Order of the Rainbow for Girls (IORG) is a Masonic social organization for girls founded in McAlester in 1922. The construction of the IORG Supreme Assembly Temple in 1950-1951 marked a seminal point in the organization's history that resulted in a landmark building both in terms of mid-twentieth-century Moderne architecture and the IORG association. The period of significance corresponds to the building's dates of construction, 1950-1951, because this represents the time in which the building attained its place in history. The period of significance does not extend beyond 1951 because doing so would be a reflection of the building's continued function rather than significance. The building is eligible for the National Register at the state level of significance to reflect the broad impact of the building which, as the headquarters of an international organization, was felt statewide. While there are other Masonic groups and various other organizations for young women in Oklahoma that have left a tangible mark on Oklahoma's cultural landscape in the form of buildings and other structures, the IORG Supreme Assembly Temple is without par in the state as the only standing headquarters building solely dedicated for and to the IORG. The IORG Supreme Assembly Temple retains a high degree of historic integrity to ably convey its historic and architectural significance.