July, 1845 - March, 1846
By the end of July, 1845, Taylor's Army of Observation had taken up positions at Corpus Christi, on the south bank of the Nueces River. When the army arrived, the location was considered ideal, and surgeons on-site evaluated it as a healthy environment for the troops. However, brackish water, poor diet, poor tents, inadequate camp sanitation, and the Gulf Coast heat soon rendered as much as 13 percent of Taylor's force unfit for duty.
Little more than a trading post during the Texas Republic period, Corpus Christi soon became a hive of activity, home to approximately 4,000 U.S. troops and perhaps as many as another 2,000 civilians who provided construction, goods and services to the Army of Observation. The U.S. army spent the next nine months encamped on the beaches of Corpus Christi and St. Joseph's Island before moving south to the Rio Grande.