The original Windmill Inn dated from the 18th Century or earlier, and occupied virtually the same site as the more recent Windmill Hotel, on the north side of the Bath Road. It tended to be known as Botham's, after the owners.

The inn had extensive gardens on the south side of the road, and the watercress beds behind the hotel were famous, and sent large quantities of watercress to London. The building itself was made of dark red brick, and had a verandah on the ground floor. Covering the front of the building was one of the finest wisterias in England.

The Salt Hill Society held their annual dinners there, and in alternate years the old Etonians held their Montem breakfasts there, until the ceremony was discontinued in 1844.

Over the years many famous people stayed at the Windmill, including cabinet ministers attending Queen Charlotte at Windsor Castle, and William Pitt the Younger, while travelling from Bath to London shortly before his death. In June 1814 the Prince Regent held a breakfast there for the Emperor of Russia, the King of Prussia and his sons, the Prince of Orange, and the Grand Duke of Oldenburg.

After the Bothams retired, the inn was let as a school, but a fire destroyed the whole building in 1882.