This mountainous region on the very eastern edge of Sonoma County has a historic reputation for producing rich, intensely-flavored wines from Cabernet Sauvignon and Syrah varietals since the 1880s.

At elevations ranging from 400 to 2,200 feet (120 to 670 m) above sea level, vines grow in a variety of soils, mainly rocky and of volcanic origin, on the western slopes and ridge tops of the Mayacamas Mountains.

[4] Crosswinds from both the Pacific Ocean to the west and San Pablo Bay in the south bring cooling maritime influences to the vineyards, but by the time the winds have travelled across the valley floor they have warmed considerably.

Cold air tends to drain off the hillside vineyards into the valley, reducing the risk of damaging frosts and allowing for a long, slow maturation period.

[2] TTB received a petition from Patrick L. Shabram on behalf of Christian Borcher, a representative of the vintners and grape growers in the area, proposed the establishment of the “Moon Mountain District Sonoma County” AVA.