The courtyards are areas of Hogwarts Castle where students often spend their breaktimes between classes when not in the Great Hall or their common rooms. A side door down the corridor off the Entrance Hall leads into the main courtyard, and a corridor with a staircase leading to the Serpentine Corridor also leads to it.

Other Courtyards:
Astronomy Tower courtyard
Central tower courtyard
Clock Tower Courtyard
Middle Courtyard
North Tower courtyard
Northern Courtyard
Northern Courtyard Annex
Storeroom courtyard
The Quad
Viaduct Courtyard
West Tower courtyard

"It was a clear, breezy day, and the grass rippled under their feet as they marched down the sloping lawns toward a smooth, flat lawn on the opposite side of the grounds to the forbidden forest, whose trees were swaying darkly in the distance." J.K. Rowling

Lawns are used for flying classes, gardens are just pretty.

The Hogwarts greenhouses are where Herbology classes are taught.

The greenhouses have statues of long, serpentine dragons running along the peaked roofs. They are home to many exotic and magical plants including some that are extremely rare, difficult to cultivate and maintain, or even dangerous, such as the Venomous Tentacula.

The Paddock is an enclosure located on the edge of the Forbidden Forest, approximately a five minute walk from Rubeus Hagrid's cabin. The Hogwarts Hippogriff herd is apparently kept in this paddock, at least at times.

The Great Lake (alternatively known as the Black Lake[3]) 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.

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) and a giant squid, which is semi-domesticated and permits students to tickle its tentacles on sunny days, when it basks in the shallows.

The lake is often said to be very cold.

The Boathouse is an underground harbour at Hogwarts School of Witchcraft and Wizardry where the boats are stored and where they dock when the first years arrive at Hogwarts Castle every 1 September.

The Owlery is a room on the top of Hogwarts Castle's West Tower, where the school owls and the owls belonging to students live during the school year. The Owlery is a circular stone room, rather cold and drafty, because none of the windows have glass in them. The lack of glass in the windows allows the owls to come and go freely. The floor is entirely covered in straw, owl droppings, and there are regurgitated skeletons of mice and voles. Many owls nestle here on perches that rise right up to the top of the tower. During the winter months, the room is very cold, to the point that one has to be careful with ice on the higher landings.

Hogwarts has its own pitch where Quidditch teams can practise, hold try-outs and play matches against each other. Each year will see a total of six inter-house matches (each house competing for the Quidditch Cup), along with numerous training sessions by each house team. The stands surrounding the pitch would be decorated differently for each Quidditch match at Hogwarts. Every second stand would be decorated with the colours of one team, and every other stand with the colours of the opposing team. Spectators would sit in between these stands.

The Forbidden Forest, also known as the Dark Forest, borders the edges of the Hogwarts School of Witchcraft and Wizardry grounds.

The forest is a very old place that holds many secrets and houses many creatures, some dark and Dangerous, others friendly. The trees in the forest are considered ancient, they are dense and rough looking from years of exposure to the elements.

As the forest's name suggests, it is strictly off limits to students — except in the case of detention, or Care of Magical Creatures lessons that occasionally take place there. Of course, with the various dangerous creatures living in the Forest, few students would even want to venture into it. Black flowers are known to grow in the forest.