[1] The boundary of San Lucas viticultural area encompasses approximately 33,920 acres (53 sq mi).

The area spreads approximately 10 by 5 miles (16 by 8 km) on a northwest-southeast axis bisected by U.S. Highway 101 as the Salinas River flows north 155 miles (249 km) from its source in San Luis Obispo County through Monterey County into Monterey Bay.

In the portion of California which later became Monterey County, missions were established at Carmel, Soledad and San Antonio.

The Spanish imposed rigidly prescribed rules under which land was parceled into pueblos, presidios, missions and ranchos.

These governors secularized the extensive landholdings of the missions by bestowing an additional 32 land grants, eight of which were in excess of 10,000 acres (16 sq mi).

As the area prospered, a large grain elevator was erected on a site which later became the town of San Lucas.

With the extension of railroad service south to San Lucas in the 1880's, the town continued to thrive and for a while its size ellipses that of King City, its immediate neighbor to the north.

Today, San Lucas AVA has approximately 8,000 acres (3,237 ha) devoted to wine grape cultivation.

The central part of the Santa Lucia Range directly west of the proposed area is composed of diatomaceous shale and massive sandstone.

The climate is cool and moist along the coast, where fog is common, and hot and dry in inland areas in the south-central portion of Monterey County.

As a result of the sequence of daytime heating and nighttime cooling as well as the effects of wind and marine fog, daily and annual temperatures in the county's interior range widely.

Most of the Salinas Valley is in the rain shadow of the coastal range and, consequently, the annual total precipitation drops to as little as 15 inches (381 mm) in areas to the south of King City.

East of the Salinas Valley, precipitation increases again on the western slopes of the Gabilan and Diablo Ranges with about 20 inches (508 mm) reported at the higher elevations.

The location of the San Lucas Viticultural Area in the southern end of the Salinas Valley allows a distinction in climatological characteristics from the rest of the county in that the area experiences heat and less intrusion of the fog common to those portions of the Salinas Valley which are closer in proximity to the Monterey Bay.

Hygrothermograph readings document a 30 °F (−1 °C) range between high and low temperatures at Almadèn's vineyard situated east of King City and a 40 °F (4 °C) range between high and low temperatures the Almadèn's vineyard situated south of San Lucas.

[3] The thermograph readings support a "warm" Climatic Region III classification for the petitioner's vineyard east of King City and a "cool" Climatic Region IV classification for the petitioner's vineyard south of San Lucas.