American versus English Golden Retrievers
The Golden Retriever breed originated in Scotland during the late 1800s where it was developed by a British aristocrat, Lord Tweedmouth. 
In 1911, the Golden Retriever breed was accepted in the British Kennel Club (KC); it was not accepted in the American Kennel Club (AKC) till 1934. 
Many people are confused what the difference is between American Golden Retrievers and English Golden Retrievers.  First of all, Golden Retrievers are a medium sized breed which were historically bred to retrieve fowls and other animals during hunting. As the breed was accepted in several countries, specifically England and the United States, two majorly different standards of breeding developed. 
American Goldens and English Goldens are not two different breeds, and both are recognized by AKC as a 'golden retriever'. English Golden Retrievers are called “Golden Retrievers” throughout Europe and the rest of the world. However, they are often called English Golden Retrievers in the United States to distinguish them from the American Goldens, due to their difference in color and physical characteristics.  
Simply stated, the English Golden Retriever is basically, "a Golden Retriever bred to the British Kennel Club (KC) standards" while an American Golden Retriever is "a Golden Retriever bred to the American Kennel Club (AKC) standards."
The most obvious difference between the American and the English Golden Retrievers is that they are generally lighter in color. They are also heavier and stockier then their American counterpart. English Goldens have a broader head and more square muzzle. The AKC will not recognize light colored retrievers while in contrast the KC does not recognize mahogany and red colored retrievers.