The Monongahela culture were an Iroquoian Native American cultural manifestation of Late Woodland peoples from AD 1050 to 1635 in present-day western Pennsylvania, western Maryland, eastern Ohio, and West Virginia. The culture was named by Mary Butler in 1939 for the Monongahela River, whose valley contains the majority of this culture's sites. The Monongahela practiced maize agriculture, and lived in well laid out villages, some of which consisted of as many as 50-100 structures. They traded with other Indian groups who in turn traded with Europeans. The Monongahela seem to have disappeared some time during the 1620s or 1630s before having significant direct contact with Europeans. Many scholars believe this to be the result of the spread of European infectious diseases. Others believe that most of the Monongahela were killed by or assimilated into either the Iroquois or the Algonquian-speaking Lenape tribes during warfare, as the more powerful tribes competed to control area hunting grounds for the fur trade. Still others claim that two severe droughts, one from 1587 to 1589 and another from 1607 to 1612, drove habitable area. Interculture chronology An internal temporal subdivision of the Monongahela culture, based on ceramic decorative attributes. Location The Monongahela culture extended in the area of the upper Ohio River system that includes the Monongahela, Youghiogheny and Casselman tributary rivers. Their region was of western Pennsylvania and the adjoining areas of eastern Ohio, West Virginia, and western Maryland. Nearly four hundred archeological sites have been recorded. The culture was contemporaneous to the bordering Fort Ancient culture in the Ohio Valley. The Monongahela is a Late Woodland horizon that coincides with the Mingo homeland and distinguishes it from the Iroquois League homeland, centered in present-day New York state. Monongahela villages originated on flood plains, but by 1250, the people had migrated to the watershed highlands and often lived on gaps between ridges. Archaeologists speculate that the move to these areas, and construction of larger, fortified villages at this time was a symptom of intergroup warfare. The Fort Hill Site (46MG12) in Morgantown, West Virginia is a nearly archeological site that includes what appears to be a Monongahela village. The site has good preservation. A human burial, animal bones, bone beads, a marginella-shell bead, shell-tempered pottery and triangular arrow points have been recovered during excavations at the site. In 2002 the site was endangered with destruction by commercial development. The majority of the 18