The Post Office was established in 1877, shortly after the founding of Hogsmeade.
When the wealthy widow who owned the Post Office at the time, Mrs. Susanne Fuhrman, gifts it to a lower class friend of hers, Miss Adelaide Filch, the Post Office briefly turns into a place of scandal. Miss Filch was pregnant at the time and as she was not married the identity of her child's father was questioned by the Daily Prophet. A lot of the employees quit, not wanting to be involved in their employer's scandal and a most of the people of Hogsmeade refuse to use the Post Office's services, which led to a massive raise to the owl sales.
Miss Filch, wanting to disappear from the public eye, decides to sell the business in a rather generous price, as its reputation 'tainted'. It is then when a young healer, Noah Hatchitt, grabs the opportunity to buy the business himself. Once the Post Office falls again in the hands of an owner free from all scandal, things go back to normal again.