Preserving the scene of the 1846 clash between Mexican and U.S. troops, Palo Alto Battlefield National Historical Park, located in the southern tip of Texas, is the only NPS site with a primary focus on the US-Mexican War. The battle was the first in a two year-long war that changed the map of North America. Walk in the footsteps of history by exploring the park's trails, go birdwatching, or take a guided tour of the site to learn more about the area’s history.

Sparked in part by the U.S. annexation of Texas, which Mexico considered part of its territory, the first shots of the Mexican-American War, or the U.S.-Mexican War, rung out on May 8, 1846 at a site now preserved as Palo Alto Battlefield National Historical Park. Fighting along the Rio Grande lasted weeks, and visitors to the park today can explore the ways soldiers and women on both sides passed their time, as well as enjoy guided tours and annual living history programs in September.