The Great Lake[4][5] (alternatively known as the Black Lake)[6] is a large body of water, freshwater and landlocked, located to the south of Hogwarts Castle. It is about half a mile in diameter and the castle's plumbing network drains into it.[2]


Hagrid and first years sailing on boats

Every school year at Hogwarts, after the Hogwarts Express arrives at Hogsmeade station, Rubeus Hagrid (or a substitute) calls the first year students to follow him to the lake shore and the Hogwarts boats. Whereupon Hagrid occupies one boat and each other boat carries up to four students. The boats then self-propels across the lake to a dock under Hogwarts Castle as per tradition.[1] At the start of the 1994–1995 school year, first year Dennis Creevey said he fell into the lake and the Giant Squid pushed him back into a boat.[3]

Upon reaching the castle, Hagrid and the first years disembark and climb the stairs to the lawn, entering the castle through the front doors. First years then waited until summoned into the Great Hall to get Sorted into their houses.[1] At the end of their first year, students take the boats back to Hogsmeade Station,[7] while most older students ride down the lane in carriages.[8]

At the end of every school year, graduating seventh years leave the school by sailing back across the lake.[9]

Saving the innocent

Harry conjuring a Patronus

On 6 June 1994, Harry Potter, Hermione Granger and Sirius Black were attacked by Dementors on the shore of the lake. Harry tried to protect them by using Patronus Charm, but he did not succeed. Before he fainted he suddenly saw a person conjuring a corporeal Patronus on the opposite side of the lake.[10] Later that night, after using Hermione's Time-Turner in Hospital Wing, they went back in time to save Black. Harry circled the lake and waited for the Dementors. Watching the events, he realised that he earlier saw himself and conjured a corporeal Patronus in deer form to flush the Dementors.[11]

Triwizard Tournament

The Second Task of the Triwizard Tournament

Students from Durmstrang Institute arrived at Hogwarts on their enchanted boat via the Great Lake. As part of the Second Task of the Triwizard Tournament, the four champions Harry Potter, Fleur Delacour, and Cedric Diggory, and Viktor Krum had to swim in the lake for one hour to rescue something that was taken from them. Harry used Gillyweed to be able to breath underwater, while Cedric and Fleur used the Bubble-Head Charm, and Krum partially Transfigured himself into a shark.[2]

Dumbledore's Funeral

White Tomb, Albus Dumbledore's resting place

In 1997, Albus Dumbledore was laid to rest in a white tomb on the shores of the lake following his death in the Battle of the Astronomy Tower.[12]

Trevor's escape

At some point in his life, Trevor managed to escape from Neville and into the lake. Both pet and owner felt a sense of relief at this.[13]



The Merpeople village in the Great Lake

The grounds of Hogwarts function partly as a nature reserve for magical creatures which have difficulty existing in Muggle-inhabited areas. There are Grindylows (vicious little water demons), Selkies (of a hardy Scottish strain)[2] and a giant squid, which is semi-domesticated and permits students to tickle its tentacles on sunny days, when it basks in the shallows.[14] The lake has a Bowtruckle Island.[15]


The lake is often said to be very cold, but Viktor Krum was known to have swam in it, wearing nothing but swimming trunks, apparently not affected by the low temperature (although this was probably due to the fact that his school, Durmstrang, is located in a place that is even colder).[16]

Lily Evans and her friends were also said to dangle their legs over the water, which could mean that there were no rules whilst they were in school against swimming in the lake.[17]

Behind the scenes

Author's comments

"The lake is the setting for the second task that the Triwizard competitors must face in Goblet of Fire, which is also my favourite task. I find it satisfyingly creepy; I like the diversity of the methods employed by the competitors to breathe underwater, and I enjoyed plumbing the depths of a part of the grounds that had never been seen before. In the original draft of Chamber of Secrets, I had Harry and Ron crash into the lake in Mr Weasley's Ford Anglia, and meet the merpeople there for the first time. At that time I had a vague notion that the lake might lead to other places, and that the merpeople might play a larger role in the later books than they did, so I thought that Harry ought to be introduced to both at this stage. However, the Whomping Willow provided a more satisfying, less distracting crash, and served a later purpose in Prisoner of Azkaban, too. The Great Lake (which is really a Scottish loch, apparently freshwater and landlocked) never did develop as a portal to other seas or rivers, although the appearance of the Durmstrang ship from its depths in Goblet of Fire hints at the fact that if you are travelling by an enchanted craft, you might be able to take a magical shortcut to other waterways."


Notes and references

Hogwarts Castle
Hogwarts grounds
Exterior Walkway · Training Grounds · Secret room near the Training Grounds · Hagrid's Hut · Hagrid's pumpkin patch · Hagrid's garden · Secret Garden · Forbidden Forest · Hogwarts greenhouses · Sundial Garden · Gatehouse · Quidditch Pitch · Incendio Challenge · Quidditch Gate · Quidditch viaduct · Broomshed · Entrance Gates · Entrance footpath · Pixie water well · Clock Tower Courtyard · Wooden Bridge · Road to Hogwarts · Ravenclaw Duelling Arena · Quidditch Training Pitch · Gargoyle Gate · White Tomb · Great Lake · Bowtruckle Island · Ravine · Road to Hogsmeade · Lawn by Forbidden Forest · Path to Owlery · Path to the Whomping Willow · Quidditch Changing Rooms
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