Dow's Port  
   Founded in 1798, and 100% family-owned. One of the great names in Port.
   http://www.dows-port.com/

Graham's Port  
   Universally acknowledged to be a leader in the field of Vintage Port.
   http://www.grahams-port.com/

The House of Sandeman  
   Specializing in Port and Sherry for more than two hundred years.
   http://www.sandeman.com/

Fonseca Guimaraens  
   One of the most famous Port houses. Site is also available in French and Portuguese.
   http://www.fonseca.pt/

Taylor, Fladgate and Yeatman  
   One of the oldest and most famous Port houses. Site also available in French and Portuguese.
   http://www.taylor.pt/

Cortes de Cima  
   Located in the Alentejo region in southeast Portugal. Harvest report and ordering information.
   http://www.cortesdecima.pt/

Quinta do Noval  
   Douro based, renowned producer of vintage Port, particularly its Nacional. Site offers information on the vineyards, the winemaking technique and the wines.
   http://www.quintadonoval.com/

Quinta do Portal  
   A family-run winemaking company based in the Douro Valley in northern Portugal. Information on its white and red wines as well as a range of Ports.
   http://www.quintadoportal.com/

José Maria da Fonseca  
   One of the oldest producers of Portuguese table wines and Setubal dessert wines. Markets under several other brand names, including Lancer's.
   http://www.jmf.pt/

Quinta de la Rosa  
   Small family-owned vineyard producing Ports, wines and olive oils. Also offers accommodations on the estate
   http://www.quintadelarosa.com/

Cavipor  
   Produces and bottles wines from several regions, and markets under a number of different brand names.
   http://www.cavipor.pt/english/index.html

Symington Port and Madeira Shippers  
   Owns Warre, Dow, Graham, Smith Woodhouse, Gould Campbell, Quinta do Vesuvio and the Madeira Wine Company.
   http://www.symington.com/

Rozès Porto  
   Includes a profile of this Port producer, along with descriptions of wines, a list of distributors, and a few recipes.
   http://www.rozes.pt/

Quinta da Murqueira  
   This winery located in one of the most antique denominated regions of the world: the Dão. Medium, medium/high and high quality wines range.
   http://www.murqueira.com/

Quinta de Roriz  
   Makers of Port and Douro table wines. Contains information about products, vineyards, history, and distributors.
   http://www.quintaderoriz.com/

Kopke Ports  
   Port producer and exporter. Includes a company history and product descriptions.
   http://www.kopkeports.com/

Casa da Ínsua  
   Dão producer of reds and a white. Includes descriptions and pictures of the manor and its gardens. Also contains product information and a property history. [Flash required]
   http://www.casadainsua.pt/

Quinta de Lemos  
   Producer in the Dão region, whose first harvest was in 2000. Includes descriptions of grape varieties, a regional history, and a view of the vineyards. [Flash required]
   http://www.quintadelemos.com/

CARM - Casa Agrícola Roboredo Madeira, Lda.  
   Produces a range of wines from organic grapes in the Douro region. Includes product information and a company overview. Also produces estate olive oils. [Flash required]
   http://www.carm.pt/

G Porto  
   Gilbert's line aimed at young adults. Includes product descriptions, cocktail recipes, and an award list. [Flash Required]
   http://www.gporto.com/

Adriano Ramos Pinto, S.A.  
   Produces Ports, dry reds, and brandy. Contains descriptions of the products, the vineyards, their museums, and the company. [Flash Required]
   http://www.ramospinto.pt/

Quinta do Tedo  
   A single quinta Port producer in the Alto Douro region. Features product descriptions, reviews, an award list, a newsletter, and a company overview.
   http://www.quintadotedo.com/

Croft Port  
   Port house founded in 1678. Presents its history, products, vineyards, how port is made, the types of port, and a glossary. [Flash required]
   http://www.croftport.com/

Calem  
   Founded more than 140 years ago, the House of Calem owns grape vineyards and ageing cellars, and produces a wide range of Ports for a number of markets.
   http://www.calem.pt/

Dão Sul - Sociedade Vitivinicola, S.A.  
   One of the new wine producers that have been revitalising the Dão region. Specializes in Quinta.
   http://www.daosul.com/

Real Companhia Velha  
   One of the leading producers of Port and the largest owner of the premium land in the Douro Valley.
   http://www.realcompanhiavelha.pt/

Smith Woodhouse Port  
   Founded in 1784, Smith Woodhouse has consistently been judged as one of the finest of all Vintage Port producers.
   http://www.smithwoodhouse.com/

Vallegre  
   Wines from Quinta da Vista Alegre's vineyards of the Douro Valley.
   http://www.vallegre.pt/

Porto Barros  
   Founded in 1913, this producer specializes in old tawnies, also producing Douro table wines and brandy. Includes product descriptions, a company history, and vineyard information.
   http://www.porto-barros.pt/