Where do the DA meetings take place in Harry Potter?

The DA meetings in Harry Potter take place in the Room of Requirement, which is located on the seventh floor of Hogwarts castle. The Room of Requirement is a magical room that appears only when someone needs it.

The DA meetings are clandestine, and the Room of Requirement is the perfect place for them, as it is hidden and can be used for any purpose. The Room of Requirement is also full of useful objects, such as weapons, books, and even a giant chessboard, which the DA uses for training.