The First Battle of Mora was part of the Taos Revolt of the Mexican–American War, between United States Army troops under Captain Israel R. Hendley, versus a militia of Hispanos (acting as Mexican nationals) and Puebloan allies in US-occupied northern New Mexico.

Also on January 20, US Army Captain Israel R. Hendley of the Second Missouri Volunteers learned of the insurrection while in command of the grazing detachment along the Pecos River, and took possession of Las Vegas with 250 men, where the insurgents were beginning to gather.

Several other US Army personnel had been wounded, by the names of Waldo, Noyes, and Culver, among others, with around 25 of the opposing militia reported dead, an unknown number injured.

Hendley, Second Missouri Volunteers, marched there from Vegas the 24th, with eighty men; he found it occupied by above one hundred and fifty men; he engaged with a number, attempting to enter the town, who were supported by a sally; he then assaulted the town; he penetrated from house to house, some of which were destroyed and into one end of their fort, where he was killed and several were wounded.

McKarney then – apprehending the return of from three hundred to five hundred men, who had left there that day for Pueblo – withdrew, and marched back to Las Vegas, with fifteen prisoners; he reported fifteen to twenty of the enemy slain.It is unknown why Hendley chose to march with inferior numbers and no artillery against such a large force.