El Camino Real de Tierra Adentro, (English: Royal Road of the Interior Land). This Royal Road was also know as the Silver Route, one which was used from 1598 to 1882. This roadpath was a Spanish built road of nearly 1600 miles in length, used by Spain for trade and as a colonization route. This Royal Road originated at Mexico City and traversed northward through north Mexico to the Rio Grande River and crossed the river at El Paso. Then, the Royal Road followed the east bank of the river north to Santa Fe where there was built a Spanish mission and eventually as far north as the San Juan Pueblo, New Mexico).

Today, the route within the United States is a part of the National Historic Trail System, which is overseen by the National Park Service (NPS) and the US Bureau of Land Management (BLM).

The Royal Road has been identified as having its begining at the Plaza Santo Domingo (19.4372799, -99.1338765) which is just a few city blocks north of the main square in Central Mexico City called the Zócalo.

Traveling north through San Miguel de Allende, Guanajuato, Dolores Hidalgo, Guanajuanto, Ojuelos, Jalisco in the south of Mexico. Then the Royal Road continued northward to Santiago de Querétaro, through Zacatecas, Durango, Ciduad Chihuahua, and Ciudad Juarez. Then, upon arriving at the Rio Grande River, the Royal Road crosses into El Paso de Norte and continues along the north bank of the river to Santa Fe, New Mexico. The Royal Royal then has its northern terminus located at Ohkay Owingeh, New Mexico where there is then northernmost Spanish mission on this Royal Road.

Long before the European arrival, the various indigenous tribes that had arisen throughout the northern central grasslands of Mexico had established a major thoroughfare for hunting and trading which later would come to be known as El Camino Real de Tierra Adentro. The route connected the peoples of the Valley of Mexico (Mexico City) with those of the north areas for the purpose of the exchange of products such as turquoise, obsidian, salt and feathers. By the year 1000 CE, there had been developed and existed a flourishing trade network spanning from Mesoamerica to as far north as the Rocky Mountains.

The city-state was built on an island in what was then Lake Texcoco in the Valley of Mexico, known as Tenochtitlan, became the capital of the Nahuatl speaking indigenous people. This city is believed to have been founded around 1325 CE and which by 1428 CE became the capital of the Aztec Empire. The exact date of the founding of the city is unclear, but the date 13 March 1325 was chosen in 1925 in order to celebrate the 600th anniversary of the city, which is now known as Mexico City. The city was the capital of the expanding Aztec Empire during the 15th century until it was captured by Spanish conquistador Hernan Cortes. He was aided by La Malinche, his interpreter and companion as well as by thousands of indigenous allies especially the Tlaxcaltec warriors.

After Tenochtitlan was subdued in 1521, Spanish conquistadors and colonists began a series of expeditions with the purpose of expanding their domains and obtaining greater wealth for the Spanish Crown. Their initial efforts led them to follow the trails established by the natives who exchanged goods between the north and the south.

Then, in 1598, John de Onate, the newly appointed colonial governor of the Santa Fe de Nuevo Mexico became lost in the desert south of Paso del Norte (El Paso) while seeking the best route to Rio del Norte (Rio Grande River). They arrived at Rio del Norte just south of present-day El Paso in the spring of the year. They then recorded the route on a map and extended it into New Mexico where Onate would establish the capital of the new Province. This trail, as mapped by Onate was to become the Camino Real de Tierra Adendro, the northernmost of the four main Royal Roads that would link link Mexico City to its colonies.