Trincheras

Trincheras is the seat of its municipality in the desert of northwestern Sonora, about 505 meters up on the bed of the Río Magdalena, which meets the Río Altar a few kilometers downstream. It had 929 residents in 2020, a good share of them named Murrieta, and lives off cattle, mining and the cheese it sells to neighboring towns.

The name comes from a misreading. In 1693 Captain Juan Mateo Manje, riding the Magdalena with Father Kino, saw the low walls ringing the hill next to town and took them for military trenches. They are in fact more than 900 terraces of river stone built for houses and ritual spaces. Between 1300 and 1450 the hill, which rises over 150 meters from the plain, was the center for farming villages in the Magdalena, Altar and Concepción valleys and was home to more than a thousand people. On the summit is the Plaza de El Caracol, with its shell-shaped stone ring and two V-shaped structures aligned with sunrise at the solstices; on the north slope is La Cancha, an open ceremonial ground. INAH opened a museum at the foot of the hill in 2011, and a community museum shows finds from the La Playa site, 10 km north.

The town itself is younger. Residents lived at San Rafael del Alamito, about 2 km away, until the river flood of 1905 pushed them to the base of the hill. Before that came gold: Spanish soldiers found placer gold in 1770, and between 1790 and 1810 as many as 10,000 people crowded into the area. The big fiesta is for San Rafael Arcángel on October 24, with live music, stalls and horse races; the day before, October 23, is Joaquín Murrieta Day, for the Murrieta the town claims as a native son. Summers are brutal, with a record of 49.5 °C, and most rain falls in July and August.