A reconnoissance was made on the morning of the 11th, with a view to the location of the batteries.  The locations selected by Captain Huger, who was sent for the purpose, were adopted.  The division of Quitman was ordered to unite with Pillow near Piedad in the evening, and after nightfall both divisions were to move to Tacubaya.  Twiggs was ordered to remain in front of the southern gates and divert the enemy’s attention.

Major Sumner with seven companies was to march at daylight and join Pillow.  Chapultepec is a natural fortification, rising one hundred and fifty feet above the valley.  A large building, the Military School, is on its summit, and it is bounded on the west by the Molino del Rey.  The grounds are surrounded by a thick wall some fifteen feet in height.  It is situated two miles from the Belen gate, and was regarded as the key to the city.  The officer in command was General D. Nicholas Bravo, an officer of skill, distinction, and courage.  Second in command was General D. Mariano Monterde.  The chief of engineers was D. Juan Cano, and D. Manuel Gamboa commandant of artillery.  Generals Noriega and Perez were afterward attached to the command.  The orders of the 11th to Quitman and Pillow were to march to Tacubaya, where they awaited further orders.

The attack was begun by the batteries of Drum and Peter Valentine Hagner, and the fire proved to be well directed.  The guns at the castle answered promptly and kept up a vigorous cannonade.  When there was some cessation of firing from the castle, Captain Lee, under direction of General Scott, using the wall of the aqueduct as a parapet, placed two pieces of artillery under Captain Horace Brooks, which opened fire.  Steptoe’s battery kept up a continuous firing.  Santa Anna, who was deceived at the point of attack, on hearing the guns of Steptoe, moved at once to Candelaria and San Antonio Garita, where he expected the attack.  At noon he repaired to Chapultepec, and, taking charge of a battalion, moved to re-enforce a work which was being attacked.  The Americans opened fire on this force and compelled it to withdraw.  General Bravo, expecting an assault, asked for re-enforcements, which General Santa Anna promised should be furnished in time.  In the meantime the Governor of the State of Mexico had arrived with seven hundred men, having reached a point near Tacubaya on the 11th, and his arrival greatly increased the Mexicans’ hopes.  Not being joined by cavalry as he expected, the Governor remained inactive on the 11th, 12th, and 13th.  Quitman’s division, with United States Marines and a company of New York volunteers, remained in the rear near the Tacubaya road during the 12th.