For almost three centuries, wagon trains loaded with silver rolled north and south along the Camino Real de Tierra Adentro, the royal road that linked Mexico City with the mining towns of the north and eventually with Santa Fe in what is now New Mexico. It was one of the longest trade routes in the Americas, carrying silver, mercury, goods, people and ideas across thousands of kilometres. In 2010 UNESCO listed a series of sites along the route, including stretches of the old road, bridges, haciendas and towns. This section, between Aculco and San Juan del Río, crosses the high plateau on the border between the State of Mexico and Querétaro.
Aculco is a pretty colonial town, designated one of Mexico's pueblos mágicos, with a main square, a church and stone houses. It is known for its dairy products, especially cheese, and for its waterfalls, the Cascadas de la Concepción and Tixhiñú, which plunge over basalt columns nearby. San Juan del Río, to the north, is a larger town with a historic centre, a long stone bridge built in the colonial period, and a tradition of opal and wine production in the surrounding area.
The old road itself survives in places as a cobbled track across the fields, with stone bridges over streams. Walking a stretch, you can imagine the mule trains, the soldiers and the merchants who passed this way. The landscape is open and rolling, with farmland, maguey plants and distant hills.
The riding is mixed. Highway 57, the main route between Mexico City and Querétaro, runs close by, a busy toll road with heavy truck traffic. The minor roads are quieter and more pleasant, but surfaces vary, and topes, the infamous Mexican speed bumps, appear without warning, often unmarked. Watch out for livestock, pedestrians and slow vehicles. The altitude here is over two thousand metres, so the air is cooler than you might expect, and afternoon thunderstorms are common in the rainy season, from June to September.
San Juan del Río has fuel, shops and restaurants, and Aculco has the basics. Try the local cheeses and a plate of barbacoa, slow-cooked lamb, a weekend specialty in the region. Check current travel advice, and avoid riding at night. The best time to visit is the dry season, from October to May.