Here is a historical chronology of southeastern Sandoval County.

10,000 BC

Estimates vary considerably, but it is generally believed that Paleo-Indians arrived in the Rio Grande Valley late in the last Ice Age, about 12,000 years ago.

700 AD

Prehistoric Indians began building above-ground communal buildings, and by 900 AD, they were probably settling into villages that evolved into the communities existing when Francisco de Coronado arrived.

1540-42 AD

Francisco de Coronado arrived at Tiguex Province in the Rio Grande Valley, where he kept his headquarters until his departure in the spring of 1542. The Tiguex War was waged against the pueblos during the winter of 1540-41.


Juan de Oñate and his band of Spanish colonists passed by what would become Bernalillo on the way north to establish New Mexico’s first capital at San Gabriel, near San Juan Pueblo.


During the Pueblo Revolt, when the Spaniards were driven out of New Mexico, they hurried along the Rio Grande on the way to El Paso. The pueblos of what would become Sandoval County were profoundly affected by the coming and going of the Spaniards.


Diego de Vargas re-conquered New Mexico.


De Vargas established the community of Bernalillo.


De Vargas died at Bernalillo after becoming ill while in pursuit of hostile Apaches.


The Mexican Revolt against Spanish rule began. Because soldiers were moved south to fight insurgents, Apaches and Navajos resumed attacks on villages in the middle Rio Grande valley.


Mexico achieves independence from Spain.

The first pack train of goods arrived in Santa Fe over what would come to be called the Santa Fe Trail. This marked the beginning of legal business between New Mexico and the United States.

Don José Leandro Perea became a trader of goods that arrived via the Santa Fe Trail.


The Mexican government made the beginnings of counties in New Mexico. Part of what would become Sandoval County was then in Santa Ana County.


Early in the Mexican War, the U.S. “Army of the West” under Gen. Stephen Watts Kearny occupied Santa Fe after officials of the Mexican government fled. Perea, living in Bernalillo, loaned money to the fledgling American government.


The treaty of Guadalupe Hidalgo was signed in Mexico, ending the Mexican War. Property rights in New Mexico were to be respected under the provisions of the treaty.


The U.S. Civil War found its way into the middle Rio Grande Valley as troops of the Union and the Confederacy moved from Texas north to Glorieta Pass, and then back south.

Confederate troops stopped long enough in Bernalillo to hunt for the wealth Perea was said to have possessed. They didn’t find it.


Santa Ana County was absorbed by Bernalillo County.


Town of Bernalillo became the seat of government for Bernalillo County.


The railroad arrived in the middle Rio Grande Valley and Albuquerque, causing the most significant change in quality of life in New Mexico history.


Bernalillo County seat is moved back to Albuquerque.


Sandoval County was created with the Town of Bernalillo as seat of government.


Los Alamos County was carved out of northeastern Sandoval County and a bit of Santa Fe County.


The American Realty and Petroleum Company (AMREP) purchased 55,000 acres of land in southeastern Sandoval County. It came to be called Rio Rancho Estates.


Rio Rancho was incorporated as a city.


Population of Rio Rancho estimated at 98,000.

Population of Sandoval County estimated at 146,000.

(Don Bullis is a Rio Rancho resident, NM centennial historian, award-winning author; named the Best Local Author in the 2018 and 2019 Rio Rancho Observer Readers’ Choice. “Ellos Pasaron por Aqui” is translated as “They Passed by Here.”)