It grows in forests with other conifers, as well as chaparral and other local mountain habitat, usually in pure stands on serpentine soils.

On Carson Ridge in Marin County, as well as Hood Mountain in Sonoma County, the species comprises a pygmy forest of trees which do not attain heights greater than 240–360 cm (8–12 feet) due to high mineral concentrations in the serpentine soil.

[4] One notable population occurs in the Cedar Mountain Ridge area of Eastern Alameda County.

According to Carl Wolf, who extensively studied the New World Cypress in the 1930s and 1940s, seed from the Cedar Mountain stand of Cupressus sargentii produced the most vigorous seedlings.

Further research lead to two proposals to move it to a new genus for new world species of cypress, Neocupressus and Hesperocyparis.