On July 23, 1845 Brigadier General Zachary Taylor, commander of the U.S. Army of Occupation, left New Orleans on the steamer Alabama with eight companies of the Third Infantry. His orders were to proceed to Texas and wait there until the Texas Convention had accepted the annexation resolution of the U.S. Congress. He was then to proceed immediately with his whole command to the western border of Texas, take up a position on or near the Rio Grande, and expel any Mexican force that attempted to cross into Texas.

On July 25, the Alabama dropped anchor off St. Joseph Island, a few miles north of the pass into Aransas Bay near the mouth of the Nueces River. By the following evening, three companies of troops had landed, and a small U.S. flag was flying from the top of a sandhill—the first ever raised by United States authority in Texas.

On July 29, Taylor attempted to take two companies of men with him to the mainland in the lighter Undine, but water in the Bay was low and the lighter ran aground after going but a few miles. There the General and his men stayed until sundown, August 1, when they were transferred to the Texas mainland in fishing boats that had gathered about the grounded lighter.

General Taylor and his men are believed to have camped beneath this massive live oak until his return to St. Joseph Island and his subsequent successful trip to Corpus Christi in September.

The Zachary Taylor Oak is located on the southeast corner of S. Pearl and E. Bay Streets, in Rockport.