On this day in 1846, Mexican and American forces clash near the Rio Grande. Tension had been mounting ever since Texas won its independence from Mexico: The two sides never agreed to a boundary after the war. Soon after Texas joined the Union, Brigadier General Zachary Taylor and an Army of Occupation were sent to Texas. They would establish the Rio Grande as the southern boundary of the United States. Taylor arrived and began building a fort (Fort Texas) near present-day Brownsville. On April 24, 1846, Taylor received reports that Mexican forces were crossing the Rio Grande. He ordered Captain Seth Thornton to investigate. Thornton’s men were up all night, moving slowly through new territory. They talked with locals, receiving conflicting reports about Mexican activity. Early on April 25, they found a plantation and went to investigate, but Thornton failed to leave a force guarding the open gate at the front of the plantation. He’d gone in and was looking for someone who might have information. His men were also inside the gates, but in varying states of readiness. Suddenly, about 1,600 Mexican soldiers appeared. The plantation lay close to the river, so Thornton’s men were penned in, trapped by the river and by fences. They were badly outnumbered, and the skirmish ended with 11 Americans dead, 6 wounded, and close to four dozen captured. Armed conflict soon followed at Fort Texas. President Polk asked Congress for a declaration of war: “Mexico has passed the boundary of the United States, has invaded our territory and shed American blood….” Congress complied on May 13. The Mexican-American War continued for more than a year, but the treaty signed in February 1848 would finally decide the matter: Mexico recognized the Rio Grande as the border of Texas. FULL STORY: TaraRoss.com