[1] When the Spanish first encountered them in the 16th century, the Piro lived in the Rio Grande River valley for a distance of about 60 miles (97 km) from north to south in present-day Socorro County.
The Piro's largest town, called San Pascual Pueblo by the Spanish, had 1,500 rooms and a population of about 2,000 people.
As a result, the Spanish gave first one, then another, Piro pueblo the name Socorro, which means "aid" or "help" (in case of problems or difficulties).
Several hundred Piros (and Tiwas) accompanied the fleeing Spaniards south to El Paso del Norte (present-day Ciudad Juárez, Mexico); others scattered and joined other Pueblo groups.
New Mexico Historical Review 88(4): 437-459 (2013) / Bletzer, Michael P., A House for Fray Alonso: The Search for Pilabo Pueblo and the First Piro Mission, Nuestra Senora del Socorro.