Mr. Darcy writes one letter to Elizabeth Bennet in Jane Austen's Pride and Prejudice. He writes it immediately after Elizabeth rejects his first marriage proposal at the Collinses' parsonage in Kent.
The long letter is one of the novel's turning points. Darcy explains why he interfered in Jane Bennet and Charles Bingley's relationship, and he gives Elizabeth his account of George Wickham's conduct toward Darcy's sister, Georgiana. Elizabeth reads the letter repeatedly and begins to recognise that her own first impressions may have been badly mistaken.
The answer is one because the question concerns letters Darcy writes to Elizabeth, not every letter mentioned in the novel. Elizabeth, Jane, Caroline Bingley, Mr. Collins, and other characters exchange numerous letters, and Darcy also communicates with people besides Elizabeth. His letter is especially memorable because it changes Elizabeth's understanding of both Darcy and Wickham, making it easy to overcount the novel's correspondence.