May, 1846 - July, 1846
The regular troops under the command of General Taylor arrived at Corpus Christi by land and sea routes during the summer of 1845. Nine months later, Taylor's army would be fired upon by Mexican troops on the Rio Grande, prompting the War Department's call for volunteers. The creation of a volunteer army to supplement the U.S. regular army presented many logistical challenges for the War Department. Construction began immediately on a fleet of steamboats to transport men and supplies to the theater of operations along the Rio Grande. In the interim, the War Department purchased all the suitable vessels it could find. The majority of volunteers arrived during the summer of 1846, although additional regiments continued to arrive in the months that followed. Almost all volunteers journeyed to the front on steamboats from their respective states that ferried them down the Mississippi River to New Orleans. From there they took ships that had been requisitioned by the War Department to Point Isabel, on the tip of South Padre Island at the mouth of the Rio Grande, many suffering severely from seasickness along the way. The journey usually took six or seven days, but the lack of steam packets at Point Isabel required many volunteers to remain on board for several days longer, until they could be ferried to shore.