Anyways, the area in which we live, according to our grant deed, was once part of the Rancho Las Juntas, the only rancho in Contra Costa County to be granted to a "gringo," who went by the name of William Welch. I found a great post on Contra Costa History that gives the full history on Welch and the land he owned here. Of his original 13,293 acre holding, we are now the proud owners of one acre!
According to the article,
The Rancho Las Juntas was formally granted to William Welch by Governor Manuel Micheltorena on February 21, 1844. This grant was for three leagues of and, as surveyed by the United States Government, contained 13,292 acres. The Spanish settlers recognized its boundaries as El Arroyo de las Nueces (walnut Creek) on the East, the Straits on the North, El Arroyo del Hambre (Alhambra Creek) on the Northwest, La Cuchilla del Reliz (the ridge of the Reliz) on the West, and Las Juntas (the junction of streams) on the South.
To approximate the borders of the original rancho, I used the information on the CoCoHistory article along with the East Contra Costa Historical Creek Map to get a sense of Welch's rancho (zoom out to see the full estimated rancho borders):
View Rancho Las Juntas in a larger map
Anyone versed in California research knows that the way in which Mexican land grants were written--using vague, transitive physical markers that neighbors agreed upon as borders--made settling ownership of land difficult once the more substantive land description requirements of the United States were expected. Many families (including Welch's) spent the years after statehood in court fighting off the invasion of squatters, combating illegal claims of ownership to their land, and enforcing the boundaries of their ranch.
Because Welch passed away relatively young, his name doesn't resonate through Contra Costa and California history the way some of his cohorts' did. But he seems to have been an impressive man all the same!