For hundreds of years, central and western New York had been inhabited by the six member nations of the Iroquois Confederacy. During the colonial period, the French, Dutch, and British coveted its strategic location along an important fur trade route. The Mohawk Valley's rich farmland also yielded great quantities of food, and the land attracted European settlers. When war broke out, Europeans living in the United States and the Iroquois fought each other for control of New York's political power, land, and commerce. A brutal civil war in the Mohawk Valley occurred on August 6, 1777, the Battle of Oriskany. Neighbor fought neighbor and transformed a quiet ravine into a bloody slaughterhouse. This lesson is based on the National Register of Historic Places files "Oriskany Battlefield" and "Fort Stanwix," primary accounts, and other sources. The lesson can be used in U.S. history, social studies, and geography courses in units about the Revolutionary War and North American Indian history. It cites relevant U.S. history standards, objectives for students, and materials needed. The lesson is divided into eight sections: (1) "About This Lesson"; (2) "Getting Started: Inquiry Question"; (3) "Setting the Stage: Historical Context"; (4) "Locating the Site: Maps" (18th-Century Travel in New York State; Iroquois Confederacy; Northern Campaign of 1777; Oriskany Battlefield); (5) "Determining the Facts: Readings" (Growing Tensions in Central New York; Battle of Oriskany; Effects of the Battle of Oriskany); (6) "Visual Evidence: Images" (Joseph Brant, 1786; Sir John Johnson, 1770s; Battle of Oriskany); (7) "Putting It All Together: Activities" (Where Do I Stand; Lost Battlefield; In the Grip of Fear); and (8) "Supplementary Resources." (BT)