Château Langoa-Barton is a Troisièmes Grand Cru Classé in St-Julien.  Château Léoville Barton is a Deuxième Grand Cru Classé, with adjacent vines, in the same appellation.  

Irish Bordeaux merchant Hugh Barton (a friend of fellow Irish merchant Bernard Phelan of Phélan Ségur) first settled in Bordeaux in 1722.  Pierre-Bernard de Pontet sold the ''Langoa'' estate (then named Pontet-Langlois) to the Bartons in 1821 and they renamed it 'Château Langoa Barton'. 

The Château was built in 1758 by a Monsieur de Pontet.  The vaulted cellars beneath the living areas of the château are a distinctive feature of visiting here.  The vineyards which became Léoville Barton were purchased in 1826, formerly part of the larger Léoville estate, which encompassed what are now Léoville-Barton, Léoville-Poyferré and Léoville Las Cases.  With no château of its own, Léoville Barton is made at Langoa and the property featured on the label is actually Langoa Barton.

The Barton's spent the majority of their time in Ireland until Ronald Barton took over.  He became the first Barton to be based at the estate.  His nephew Anthony Barton, who took over in 1983, did much to define the austere, classical style here, favouring traditional vinification and as little intervention as possible, to allow the wine to express its terroir.  The estate is now run by Anthony's daughter, Lilian Sartorius-Barton.

Langoa is in a slightly cooler microclimate to Léoville.  The 20 hectares are planted on gravelly with clay subsoil, to a mix of 57% Cabernet Sauvignon, 34% Merlot and 9% Cabernet Franc.  The vines are on average 37 years old.  Around 7,500 cases are produced each year.  

At Léoville-Barton, the 50 hectares of vineyards are planted to 74% Cabernet Sauvignon, 23% Merlot and 3% Cabernet Franc.  The soils are gravel over clay, with a high proportion of old vines.