Queensgate is an abandoned castle of the Night's Watch, standing on the Wall between Deep Lake and Castle Black. Of old it was called Snowgate, and it bore that name for thousands of years before a queen's visit gave it another.
The Queen's Name
When Good Queen Alysanne, wife to King Jaehaerys I, flew to the Wall on her dragon Silverwing, she lodged at Snowgate, and the black brothers renamed the castle Queensgate in her honor. The queen proved a great friend to the Watch, enlarging its lands and paying for the raising of Deep Lake, so the name was kept ever after. Honor could not fill its halls, however, and like most castles of the Wall, Queensgate now stands empty, its gate sealed with ice and stone.