The wine regions of Bordeaux are a large number of wine growing areas, differing widely in size and sometimes overlapping, which lie within the overarching wine region of Bordeaux, centred on the city of Bordeaux and covering the whole area of the Gironde department of Aquitaine.
The Bordeaux region is naturally divided by the Gironde Estuary into a Left Bank area which includes the Médoc and Graves and a Right Bank area which includes the Libournais, Bourg and Blaye. The Médoc is itself divided into Haut-Médoc (the upstream or southern portion) and Bas-Médoc (the downstream or northern portion, often referred to simply as "Médoc").
There are various sub-regions within the Haut-Médoc, including St-Estèphe, Pauillac, St.-Julien and Margaux and the less well known areas of AOC Moulis and Listrac. Graves includes the sub-regions of Pessac-Léognan and Sauternes (among others), and Sauternes in turn includes the sub-region of Barsac. The Libournais includes the sub-regions of Saint-Émilion and Pomerol (among others). There is an additional wine region of Entre-Deux-Mers, so called because it lies between the Garonne and Dordogne rivers, which combine to form the Gironde. This region contains several less well known sweet wine areas of Cadillac and St. Croix de Mont.
All of these regions (except the Libournais) have their own appellation and are governed by Appellation d'origine contrôlée laws which dictate the permissible grape varieties, alcohol level, methods of pruning and picking, density of planting and appropriate yields as well as various winemaking techniques. Bordeaux wine labels will usually include the region on the front if all the grapes have been harvested in a specific region and the wine otherwise complies with the AOC requirements. There are about 50 AOCs applicable to the Bordeaux region.
Both red and white Bordeaux wines are almost invariably blended. The permissible grape varieties in red Bordeaux are: Cabernet Sauvignon, Merlot, Cabernet Franc, Malbec and Petit Verdot. While wine making styles vary, a rule of thumb is that the Left Bank is predominantly Cabernet Sauvignon based with the Right Bank being more Merlot based. The Graves area produces both red wine (from the grapes previously mentioned) and white wine from the Sauvignon blanc, Sémillon and Muscadelle grapes. The area of Sauternes (including Barsac) is known for its botrytized dessert wines.
There are a number of classifications of Bordeaux wines, covering different regions. None of these attempts to be a comprehensive classification of all the producers within a given area: rather, only the producers (universally known as châteaux, although not usually possessing the architectural grandeur that might imply) perceived as being of an unusually high standard are included in the classification. The châteaux included in the classification are referred to as classed or classé, and those not included are referred to as unclassed. Some classifications sub-divide the classed châteaux, according to the perceived quality. On the Left Bank, the Bordeaux Wine Official Classification of 1855 is the starting point for classification. Although this purports to be a classification of all Bordeaux wine, it in fact exclusively lists red wine producers from the Haut-Médoc plus Château Haut-Brion of Graves, and (in a separate list) sweet white wine producers from Sauternes (including Barsac). Estates in the Médoc which were not classified in that listing may be classified under the Cru Bourgeois label. In 1953, a Classification of Graves wine was produced. Although this purports to classify the whole of Graves, it exclusively lists châteaux in Pessac-Léognan. In 1954, a separate classification of Saint-Émilion wine was set up for this Right Bank region.