View of the Palo Alto Battlefield National Historical Park in Brownsville, Texas. The park preserves the grounds of the May 8, 1846, Battle of Palo Alto, the first major conflict in a border dispute that soon precipitated the Mexican-American War. The United States Army victory here, and soon afterward at the battle of Resaca de la Plata a few miles away in what is now Brownsville, made the invasion of Mexico possible. The historic site portrays the battle and the war, and its causes and consequences, from the perspectives of both the United States and Mexico.