The advance party of skirmishers under Captain Mackall had been pursuing Arista's army throughout the morning and early afternoon, and as they reached the brush around the resaca the group came under heavy rifle and artillery fire.
[3] Mackall attempted to press further in order to gain a clearer view of the Mexican position, but, lacking the firepower of Taylor's main body, was ultimately forced to retreat and await reinforcements.
In fact, Mexico's declaration of war against the United States did not even reach President James Polk in Washington D.C. until May 9, the very day that the Battle of Resaca de la Palma was fought.
[5] The overwhelming success of General Taylor against the Mexican forces colored the American perception of the war, and Congress' call for the raising of new regiments (ratified prior to the news of the victory) was quickly overfilled by thousands of eager volunteers.
[6] The mix of different types of shot used by Ridgely's gunners also proved to be quite potent and allowed them to respond to a variety of battlefield situations much more rapidly than the Mexican artillery, especially when confronting cavalry charges.
[6] The Mexican Army left behind a number of artillery pieces, the colors of Mexico's lauded Tampico Battalion, and other baggage which included Arista's writing desk and silver service.
One of the most important finds among the documents was General Arista's personal map of the Eastern Interior Department, which provided a detailed, up-to-date view of the surrounding regions of Tamaulipas, Nuevo León, and Coahuila.
[7] The capture of this map provided Taylor with an invaluable resource in planning the next phase of his campaign, especially now that the fighting had moved to the opposite side of the Rio Grande, where American intelligence was less reliable.
[8] The rout of General Arista's army at Resaca de la Palma also relieved the Mexican siege of Fort Texas, where a garrison had been left following Taylor's move to Point Isabel prior to the Battle of Palo Alto.
[4] As the Mexican lines deteriorated, the batteries at Fort Texas were able to contribute to the rout, joining with Taylor's advance troops in forcing Arista's army back across the Rio Grande.
[9]: 176 General Arista was also recognized for his care of captured American soldiers, especially pertaining to the men belonging to Captain Seth Thornton's cavalry patrol which had been ambushed within the first days of the conflict.