Greenway, also known as Greenway House, is an estate on the River Dart near Galmpton in Devon, England. Once the home of the author Agatha Christie, it is now owned by the National Trust.

Dame Agatha Mary Clarissa Christie, Lady Mallowan, was an English writer known for her 66 detective novels and 14 short story collections, particularly those revolving around fictional detectives Hercule Poirot and Miss Marple. She also wrote the world's longest-running play, the murder mystery The Mousetrap, which has been performed in the West End of London since 1952. A writer during the "Golden Age of Detective Fiction", Christie has been called the "Queen of Crime"—a moniker which is now trademarked by her estate—or the "Queen of Mystery". She also wrote six novels under the pseudonym Mary Westmacott. In 1971, she was made a Dame (DBE) by Queen Elizabeth II for her contributions to literature. Guinness World Records lists Christie as the best-selling fiction writer of all time, her novels having sold more than two billion copies.