Statement of Significance (as of designation - July 19, 1964):
The prehistoric platform mound and associated archeological remains at Pueblo Grande represent one of the last surviving urban architectural sites of its kind in the Southwestern United States. There is evidence that between A.D. 1100 and 1400, Pueblo Grande served as a Hohokam administration center for a major irrigation canal system. Due to its prehistoric significance, pre-eminent archeologists have conducted research at Pueblo Grande since the 1880's. During 2003, Hohokam-Pima Irrigation Sites, remnants of the prehistoric (1150-1450) canal system used to irrigate crops in the Salt River Valley, that had been a separate NHL designated I 5/23/1963, were incorporated into the Pueblo Grande Ruin & Irrigation Sites NHL. Nineteenth-century Anglo settlers used portions of this extensive and efficient network of canals in later expanded reclamation projects.