For a castle so well protected by ancient charms, there are many ways to get in!
Via Hogsmeade
* Honeydukes cellar to the witch with the hump in Hogwarts (PoA)
* Shrieking Shack to the Whomping Willow (PoA)
* Other paths now caved in or known by Filch (PoA)
* Route students regularly take to get to and from Hogsmeade on days out.
* The Hogs Head secret path to the Room of requirement behind Ariana(DH)
Via Forbidden Forest
* Mr <PERSON> in Goblet of Fire, under the imperius curse, stumbles in through the forest (GoF).
* <PERSON> escaping after failing probation under Umbridge rule (OoTP)
* <PERSON> bringing in <PERSON> to the Forbidden Forest and thus access to Hogwarts (OoTP)
Via Knight Bus
* Just outside the school gates (Order of the Phoenix)
Via Floo Power
* Specially arranged to return <PERSON> and <PERSON> after Christmas (HBP)
Via Air
* Madame Maxine and the Beauxbaton Delegation (Goblet of Fire)
* <PERSON> and <PERSON> flying away after creating a swamp in a corridor(OOTP)
* <PERSON> and <PERSON> flying in on brooms after getting the fake horcrux (Half Blood Prince, although <PERSON> added charms this year due to the increased danger that he had to unlock on the way back)
* Thestrals in the forest flying out (OoTP)
* Friends of <PERSON> fly to the highest tower to get <PERSON> (PS)
* When <PERSON> escaped riding on BuckBeak (PoA)
Via Sea/Lake
* <PERSON> and the <PERSON> delegation arriving via ship/submarine (GoF)
* Boats that take the first years in (PS)
Via Walk from Hogwarts Express terminating station
* <PERSON> had to walk with <PERSON> on the route the Threstrals usually pull carriages of students after arriving from Kings Cross (HBP)
Via Cupboard
* The cupboard/Vanishing Cabinet used to get Death Eaters in that <PERSON> was repairing throughout book 6 (HBP)
Via Phoenix?
* Not too sure about the extent and range of <PERSON> powers, but he seemed to be able to send <PERSON> messages, and took <PERSON> away (destination unknown) (OoTP)
Via Portkeys
* Used to get <PERSON> and <PERSON> out at Christmas (OoTP)
* Used to get <PERSON> back to Hogwarts after ministry fight (OoTP)
* Used to deliver <PERSON> for use in <PERSON>'s resurrection spell, and again by <PERSON> to escape back to Hogwarts with <PERSON>'s body (GoF)
Any extras are welcome :) 194