The United States Army and Urban Combat in the Nineteenth Century, Jonathan A. Beall, War In History, 16:2 (2009), pp. 157-188.
Searching for precedents to the street fight that the Army of the Potomac performed at Fredericksburg in December 1862, CWL found only one: Monterrey Mexico. Beall's article on the dearth of tactics and strategy regarding street-to-street fighting sets forth a story of unexpected tactical situations. Theorists of the early 19th century, such of Jomini and voc Clausewitz, suggested that an entrenched camp could be attacked only in lightly manned. Mahan, an American thinker and educator, concentrated on fortifying defensively rather than siegecraft. The street fighting that occurred in Monterrey and Fredericksburg was not after a siege. Deploying marching columns and keeping battle lines straight in the face of the enemy was, for the most part, the extent of small unit tactics taught at West Point.
With 2,400 soldiers Taylor at the Battle of Palo Alto he utilized his light artillery rather than make a bayonet charge. Because the Mexican line was thin and stretched for a mile Taylor ordered the guns to advance in front of the army, fire, and then quickly and frequently change position and drove the Mexicans from the field with 200 in losses. At the Battle of Resaca de la Palm Taylor advanced with a force of 1,700 and using dragoons turned the Mexican army's flank and forced them to realign their defensive position. Taylor's army held firm against two counterattacks. At the Battle of Monterrey Taylor’s army was heavily reinforced by regular army and volunteer units, raising his army's to 6,000 soldiers.
Against 7,000 Mexican regulars and 3,000 Mexican militia, Taylor attempted to breach the city’s walls with light artillery. During an assault heavy Mexican guns were captured by forces and were turned on the city. Savage house to house fighting ensued and Monterrey fell to American forces. Monterrey's 10,000+ residents lived on narrow but straight streets that ran in the cardinal points of the compass. The main plaza that contained the cathedral and the municipal building was on the eastern side of Monterrey. The Mexican army defended two major hills to the west and outside the city. To the north and outside the city a redoubt with bastions held eight canons and 400 Mexican soldiers. Two other redoubts were east of the city.Nearly all the streets in Monterrey ran straight and parallel with intersections at right angles. The houses on these streets were protected by heavy doors and shutters had were covered by flat roofs with sandbagged stone parapets. Many houses had loopholes in the walls for muskets. Within this variety of defenses 7,300 Mexicans defended the city against 6,300 Americans.
Taylor's tactics began with the capture of the major road that would have been the only way of retreat for the Mexicans. He followed with diversionary attacks on the eastern forts while his main attack included a foray into Monterrey which initiated Taylor's efforts at street fighting. The 1st Ohio advanced into the city and without maps became disoriented. Heavy firing by the Mexicans forced the 1st Ohio out of the city as both sides adapted to disorganization caused by every man taking a position when he could get a fire on the fort [bastion in the city] and not be wholly exposed himself.
The next effort came the following day when the 3rd U.S. Infantry went into the city and stayed off the streets and moved to the centre of Monterrey by breaking through interior walls and clearing rooms. Interior walls were breached; 6 pound shells with short fuses were tossed in the adjacent room. After the room was cleared access to the roof was gained and support given to those who who fired from doorways and windows. Crossing an intersecting street was difficult because the Mexicans had erected barricades on them near the intersection. Light artillery pieces were used to supply cover from musket fire coming from the barricades. Groups of 50 or 60 operated as building clearing squads. Americans had decentralized their units, avoided engaging the Mexicans in the streets, and abandoned their column and linear formations. Multiple routes of advances were used which maintained the initiative on the western side of the town. The effort was duplicated on the eastern side of the town, but inside of breaching interior walls with battering rams, soldiers wielding axes attacked doors while be covered by suppressing fire. Then battering rams would be put to work and a block of houses cleared.
Taylor ordered the attackers on the eastern side be brought out of the side so a bombardment could commence. The Mexicans then reinforced their defenders on the western side of the city. The attackers on the western side became relentless at this time and increasingly used courtyards as means of access to buildings, colt revolvers to clear rooms and immediately seize rooftops. Light artillery pieces were hauled to the roof tops and fired with effect into the center bastion of the city. Soldiers from Tennessee and Mississippi were the most active in these assaults. American forces did not loose the initiative after the first blocks were breached and Mexican forces surrendered the next day.
Top Image: American Army Marches Toward Monterrey Mexico; artist: Adolphe Jean-Baptiste
Middle and Bottom Images: War and Game