Appointed in 1764 by the governor of the Spanish colony of Nuevo Santander, Captain Blas Maria de la Garza Falcon (1712-1767) established an outpost and way station (8 miles east), the first in present-day Nueces County. He was commissioned to explore the coast and establish a mission for Christianizing the Indians. By 1766 he had moved his family, friends and herds of livestock to what was called Rancho de Don Blas or Santa Petronila Ranch. Until 1836 many colonists came from the Rio Grande area.
The ranch served as headquarters for expeditions including those led by Falcon and his son Alferez Don Joseph Antonio de la Garza who explored the islands along the Gulf Coast. Falcon probably named Santa Gertrudis Creek after his only daughter, Gertrudis de la Garza. He played an important role in settling towns along the Rio Grande and Nueces River and Padre, Mustang and St Joseph's Islands. Soldiers at the garrison patrolled the region against the fierce Karankawa Indians and foreign invasion. Many colonists returned to the Rio Grande settlements because of Indian raids and the Texas War for Independence (1836). After the war they reestablished homes here. Many of their descendants still live in the area.