April 1, 2023
The J & J Ranch project includes the oldest—as well as some of the newest—homes in Contra Costa County. The 20-acre hillside site of the newly developed, 13-lot J & J Ranch project contains at its center the oldest surviving house in Contra Costa County, an adobe structure originally built in 1841. The house was built by Don Joaquin Moraga on the once-sprawling Rancho Laguna De los Palos Colorados, a 13,316-acre land grant from the Mexican government in 1835, which included what is now Moraga and portions of Orinda and Lafayette. A pre-development geotechnical investigation of the site by Alan Kropp & Associates included a comprehensive subsurface investigation, in which two large-diameter borings were logged by lowering our engineering geologist down the bore shaft, deep into the earth, to examine the subsurface strata “in-place.” A number of site stability issues were identified by our pre-development investigation and corrected with an extensive remedial grading program that first broke ground in 2017. The site development has included the extension of Adobe Lane and associated underground utilities into the new subdivision, as well as the creation of two new cul-de-sacs—all the while preserving the historic adobe structure at the heart of the development. With the subdivision improvements now largely completed, several of the newest and most exclusive custom homes in Contra Costa County are currently in construction on the site, and the site developer (Branagh Development) is in negotiations to sell the historic adobe home and the surrounding two-acre lot to the Friends of the Joaquin Moraga Adobe, who plan to restore the structure and turn it into a house museum.