Transmontano is a Vinho Regional (equivalent to IGT and IGP) and viticultural region within the Tras-os-Montes e Alto Douro administrative province, in the northeastern corner of Portugal. Within the same boundaries lies the higher-level Tras-os-Montes DOC appellation. As its name (across the mountains) implies, Transmontano lies on the eastern, inland side of the low mountains that separate the Douro Valley from Toro and Rueda, and thus Portugal from Spain.
Wine production has long been an important part of this rural economy. However, the lack of international renown for most Portuguese table wines during the 20th Century meant many locals were forced to relocate to the cities in search of work. Portugal's current wine resurgence is bringing some degree of prosperity back to the region.
The region's shallow granite soils are not well suited to arable crops or livestock, but they are ideal for viticulture; in fact, more vines are planted here the country. However the area is one of Portugal's driest wine regions, which makes for low yields, so although Transmontano has more vines than any other Portuguese region, both Tejo and Estremadura - Lisboa produce more wine.
The mountains cast a rain shadow which shelters the region from (or perhaps deprives it of) rains blowing in from the Atlantic. Consequently the prime viticultural areas here (those that tend to be responsible for Tras-os-Montes DOC wines) follow the paths of the region's four main rivers: the Douro, the Sabor, the Tua and the Tamega.
The vineyards sit at varying altitudes and as a result produce various wine styles. Vineyards located in cooler, higher-altitude areas typically produce wines that are lighter in alcohol and lower in body, while the lower-lying areas are the source of fuller-bodied wines, which are often high in alcohol. Sourced mostly from highland vineyards, the most internationally famous Transmontano wine brand is the semi-sweet, semi-sparkling rosé Mateus.
A broad array of indigenous and international red and white grape varieties are grown in the region. Indigenous varieties include Boal Branco and Malvasia Fina (the naming of these seems interchangable in the region) Côdiga do Larinho, Síria, Tinta Roriz (Tempranillo), Touriga Franca, Touriga Nacional and Trincadeira.
The entire Tras-os-Montes e Alto Douro region is entitled to use the Transmontano VR title on wine labels. This used to include producers in the Douro DOC, whose vineyards are famous as the source of port wines, but these are now covered by their own Duriense VR title.