Armijo attempted to expand Hispanic settlements and bolster the security of New Mexico by granting large acreages of land to prominent individuals.

[5] William Wroth wrote on the New Mexico State Historian's Website, "Governor Armijo was portrayed by George Wilkins Kendall as having been an uneducated man from a poor family who worked his way up by stealing.

This gross caricature was Kendall's way of vilifying Armijo due to his perception that the Governor had treated him unfairly in 1841 in the capture of the disastrous Texas Santa Fe expedition.

Angélico Chávez wrote, "Manuel Armijo's character as Governor and as a man has been unjustly painted in sources too numerous to mention here.

In 1827, he was appointed governor of New Mexico, but in 1828 he returned from Santa Fe to Albuquerque as a wealthy merchant in sheep and wool blankets, acting as alcalde again.

[9] Armijo wrote to the government requesting federal troops, and trained soldiers under Lt. Col. Cayetano Justiniani of the Veracruz dragoons arrived in early January 1838.

Armijo was a friend, a business partner, and a rumored lover of the wealthy Santa Fe saloon owner Maria Gertrudis "Tules" Barceló.

[14] Armijo approved grants of land totaling 9,700,000 acres (39,000 km2) to New Mexican citizens (including several prominent Anglos who had become Mexican citizens)[15] For example, in January 1841 Charles Beaubien and Guadalupe Miranda petitioned Armijo for a grant of 1,741,764 acres (7,048.67 km2) of land east of the Sangre de Cristo range.

The U.S., after taking control of New Mexico, adjudicated the grants and approved many of them as legal, but the ultimate owners of the land became in large part the Anglos and Hispanic politicians and speculators known as the Santa Fe Ring.

Armijo heard of the plan in late June from an American business partner who arrived with a caravan on the Santa Fe Trail.

[2][18][19] On August 4, as Kearny and his army crossed what is now the border between Colorado and New Mexico, Armijo signed a power of attorney so that an associate could take care of his affairs after he left.

[18] Next Kearny sent Anglo-American trader, "James Magoffin, along with Captain Philip St. George Cooke and twelve dragoons to meet with the governor.

According to Alvarez, despite knowing the size and strength of the United States forces, Governor Armijo was the only government official who wanted to defend New Mexico while the others were convinced that a disastrous defeat would be the outcome of any futile attempt at defense.

When he saw that his militia had weapons of spears, bows, arrows and outdated firearms, he knew they were outnumbered, under-trained and under-equipped to meet the regular United States' army.

[18] Around this same time some Santa Feans talked of killing the American traders in the town, but Armijo put a stop to the plan and dismissed Archuleta.

[24] In any case, at the Battle of Santa Fe, Armijo set up a position in Apache Canyon, a narrow pass about 10 miles (16 km) southeast of the city,[25] but decided not to fight before the American army was even in sight.

[27][28][29] One of his sons, Manuel Armijo, served as Colonel of the New Mexico Militia in the American Civil War, participating in the Battle of Valverde.