Tejano settlements developed in three distinct regions: the northern Nacogdoches region, the Bexar–Goliad region along the San Antonio River, and the frontier between the Nueces River and the Rio Grande, an area used largely for ranching. These populations shared certain characteristics, yet they were independent of one another. The main unifying factor was their shared responsibility for defending the northern frontier of New Spain. Some of the first settlers were Isleños from the Canary Islands. Their families were among the first to reside at the Presidio San Antonio de Bexar in 1731, which is modern-day San Antonio, Texas.