U.S.A.

The contiguous states and Hawaii have a nationally coordinated topographical mapping; separate mapping systems exist for Alaska. The area includes significant mountain ranges and plains. Surface geology ranges from Quaternary deposits to pre-Cambrian crystalline bedrock.

Monitoring networks in different environments record, among other things, temperature, precipitation and soil moisture. For the analysis of regional temperature and precipitation conditions, the country is divided into climate units.

Viticulture includes varieties of the species Vitis vinifera as well as interspecific and winter-hardy hybrids. Documented wine grapes include Cabernet Sauvignon, Chardonnay, Merlot, Pinot Noir, Sauvignon Blanc, Syrah and Zinfandel.

Research focuses on irrigation management in drought and heat stress. In regions with extreme cold, measures by winemakers may require burying Vitis-vinifera vines for winter protection.

Geographical indications for wine may refer to the country, a state, a county, or a federally recognized American Viticultural Area. Such an AVA is a delimited wine-growing area that differs from its surroundings through geographic or climatic characteristics. The boundaries and descriptions of the recognized AVAs are set out in 27 CFR Part 9.

For wine bearing an AVA designation, at least 85 percent of the grapes used must come from that area. The wine must also be completely produced in the state, or one of the states, in which the area is located. The 18th Amendment was ratified on 16 January 1919; nationwide enforcement of Prohibition began on 17 January 1920. The 21st Amendment repealed it on 5 December 1933.