The Adobe

The John Marsh Adobe was the first home on Rancho Los Méganos, built in the early 1840s and serving as Dr. John Marsh’s residence for nearly twenty years. As the earliest non‑Hispanic settler in Contra Costa County, Marsh’s adobe became a key waypoint for emigrants arriving via the Overland Trail and a center of early ranching activity in the region.

Although the adobe no longer stands, its location remains historically significant. It reflects the intersection of Indigenous Bay Miwok and Volvon history, Mexican‑era landholding, and California’s transition to statehood. The adobe era laid the foundation for Marsh’s later construction of the Stone House in 1856.

Today, the adobe site lies within Marsh Creek State Historic Park, where the John Marsh Historic Trust envisions a future reconstruction to help visitors experience the earliest chapter of life at Rancho Los Méganos.