The ministry of magic has an unfounded fear that Dumbledore wants to take over the ministry.
In the Room of Requirement.
Ginny Weasley thought of the name. She thought of that name for their "anti-Ministry of Magic" group, because she said the Ministry is afraid of Dumbledore.
When Harry syarts teaching his own select few students called dumbledores army or ,D.A. for short, magic himself
Hogs Head in Hogsmead
They considered calling themselves the Anti-Umbridge League, the Ministry of Magic are Morons Group, the Defence Association or Dumbledore's Army
Many people. That fanfic of Thanfiction is really dark, and its sequel (Slaught) is even more dark.
The headquarters of the Ministry of Defence for the British army located in the United Kingdom is: Ministry of Defence, White Hall, London, SW1A 2HB, United Kingdom.
Enemies and their equipment.
The Philistine army.
Susan Bones goes to Hogwarts school and is a member of hufflepuff and is also a member of dumbledores army. Sadly her mother [Amelia bones] got murdered by Voldemort.
Well, the books are quite misleading and you don't find out until the near-end but yes ("Sanpe") Snape is on Dumbledore's side
It seems like the enemies of the Provisional Irish Republican Army would be the British. That's what the research that I did on this topic.