The Regiment would serve throughout the campaigns in Mexico, most notably; Vera Cruz, Contreras, Churubusco, Chapultepec, and the Gaita de Belen (a main gate into Mexico City). At the Battle of Churubusco on August 20, 1847, Colonel Pierce Mason Butler and Lieutenant Colonel Dickinson were both mortally wounded while carrying the flag. Dickinson passed the flag to Major Adley H. Gladden who passed it to Lieutenant Baker of Company A, who carried it a short time before giving out due to illness. He turned the banner over to Major Gladden. Major Gladden passed the flag to Private Patrick Leonard of Company H, who carried it through the remainder of the battle. At the Battle of Chapultepec and the fighting at the Belen Gate on September 13, 1847, this flag was the first American Colors that were raised over the City of Mexico.