Stone House of John Marsh, Gothic Revival mansion in Brentwood, US

The Stone House of John Marsh is a three-story Gothic Revival mansion in Marsh Creek State Park near Brentwood, begun in 1853 and finished in 1856 to designs by San Francisco architect Thomas Boyd. Its walls are clad in locally quarried sandstone, and it is the earliest substantial building in Contra Costa County not built entirely of adobe. An observation tower, originally 65 feet (20 m) high, was built so Marsh could watch for approaching strangers; the stone tower collapsed in the 1868 Hayward earthquake and its wooden replacement fell after the 1906 quake.

John Marsh began his Gothic Revival stone house in 1853 and finished it in 1856, after hiring San Francisco architect Thomas Boyd following his 1851 marriage to Abby Tuck, who chose the site along Marsh Creek. Abby died in 1855, before completion. The house is the earliest substantial building in Contra Costa County not built entirely of adobe.

The park's archaeological sites span 7,000 years. Around 4,000 years ago the Windmiller culture appeared here, one of fewer than ten Windmiller sites identified statewide; the Meganos people carried it on until about 1,000 years ago. Excavations have found human remains and burial sites, which park planners intend to protect.

Access to the property is limited, so plan ahead and check for visiting arrangements before arriving at the site. The location sits outside the main town center, making private transportation the most practical way to reach it.

The observation tower was built so John Marsh could spot approaching cattle rustlers from far off. It proved vulnerable to earthquakes: the original stone tower collapsed in the 1868 Hayward earthquake, and its wooden replacement fell after the 1906 quake.