Originally settled by ranchers and farmers in the 1850s, Monticello was the headquarters for the Southern Apache Agency until 1874. This was part of the greater Indian reservation system, by the early 1870s 1500 Apaches were located about 15 miles to the northwest of Monticello.

Originally named Canada Alamosa, the town was renamed Monticello in 1881. During its peak, the population was nearly one thousand - mostly farmers and ranchers. The town was laid out in typical Spanish style, with a central plaza surrounded by adobe buildings. The outer walls of the building were extra thick, with gunsight holes strategically placed for defense.

Today Monticello is still an active town with something on the order of one hundred residents. The church is currently used for special occasions and feast days. The plaza plays host to two yearly fiestas, the Monticello Fiesta held in February and the Harvest Fiesta held in October.

Monticello is located approximately 25 miles north of T or C. Take NM -181 exit 89 toward NM-52/Cuchillo/Monticello. Turn left onto NM-181/US-85. After 1 mile, turn right. Turn left onto C-CO29, which becomes NM-142 (portions unpaved).