The Casa do Douro was established in 1932 as the Douro Winemakers' Union Federation.
Its headquarters, dating from 1944, with its exterior clad in polished granite, was designed by Portuguese architect José Porto. Inside, noteworthy are the stained-glass window by painter Lino António and the grand hall, with three central crystal chandeliers, shaped like clusters and weighing over a ton, as well as the Pombaline marker identified with the number 1. When the Douro region was first demarcated, 331 granite markers were placed. The Pombaline markers (so named because the demarcation was designed by the Marquis of Pombal) are all different and share the word Feitoria (vinho de feitoria, synonymous with better-quality wine) and the year (1758 or 1761). At the time, wines were classified according to their quality and destination. The best wine, known as Vinho de Feitoria, was sent to England; Vinho de Embarque was exported to Brazil; and Vinho de Ramo was sold in Portugal.
The stained glass window of the Casa do Douro, by painter Lino António, encapsulates the entire dynamic of the Douro Demarcated Region. It covers an area of 50m2 and forms a triptych. In the center panel, we see three large figures. The central figure represents the Casa do Douro and holds a scroll that reads "... Casa do Douro, decree 21,883, November 1932." This means that the government, through the aforementioned Decree-Law, created the Union Federation of Winegrowers of the Douro Region in November 1932, now known as Casa do Douro.