When he wrote his memoirs, an aged and terminally ill Ulysses S. Grant could still vividly recall his introduction to fighting at the opening battle of the Mexican-American War of 1846-1848. He described marching through shoulder-high grass and dodging cannonballs on the prairie of Palo Alto, near the Texas-Mexican border, where American advances in artillery and ammunition decimated the much larger Mexican army while keeping American casualties low. Because U.S. Army officers failed to publish an official account of the battle, historians of the war have relied on Mexican documents, now called into question by recent archaeological surveys of Palo Alto National Historic Battlefield. Battlefield archaeology has only recently gained respectability as a valuable way to analyze combat experience. In the case of Palo Alto, fought 150 years ago this May, archaeology has helped to determine the veracity of conflicting accounts in historical documents.