Gerudo Valley

Located in the northwest corner of Hyrule in Ocarina of Time, Gerudo Valley is a blisteringly hot valley. It leads to the Gerudo's Fortress, home of the proud female warrior race of Gerudo. Beyond lies the Haunted Wasteland, a harsh and unforgiving desert. Zora's River passes through the bottom of the valley, whose water-flow ultimately leads to Lake Hylia.

During Link's childhood, the path to Gerudo's Fortress is blocked by Gerudo guards, making it impossible to get to the other side of the valley. Once the young hero retrieves the Master Sword from its pedestal, the bridge spanning across the chasm will have been destroyed by the Gerudo, forcing Link to use either the Longshot or Epona to get across. There will also be a tent set up near the entrance to the Gerudo's Fortress that is home to the Carpenters who helped build up Kakariko Village; however, all of the carpenters except their boss have left in hopes of joining the Gerudo and become thieves themselves. When Link travels to the fortress, he finds out that all four of the carpenters have been imprisoned by the Gerudo, and once he frees all of them, the carpenters return to their previous job to repair the bridge.

Inside the carpenters' tent is the Running Man who, after the bridge is repaired, will challenge the Hero of Time to a race to the bridge that leads to the Kokiri Forest.

There is a crag where a box lies. Link can fly to this spot with the help of a Cucco, and find a Piece of Heart inside the box. The water below the valley in which Zora's River flows is infested with Octoroks as well as giant, rolling boulders. Link can take a dive from the bridge high above and land on the highest portion of river, which has a small platform with a patch of soil where Link can plant a Magic Bean. Behind the waterfall is a ladder that leads to a ledge with a second Piece of Heart. The young hero can then let the current take him back to the upper part of Lake Hylia.

Theoretical Connection & Explanation
In Twilight Princess, Gerudo Valley is not present at all (although there is a small valley/canyon between the Gerudo Desert and the Arbiter's Grounds). However, beyond this canyon lies a large fortress-like settlement before the entrance to the Arbiter's Grounds, so either by sheer coincidence, or a major geographical shift, the Gerudo Valley and/or Gerudo's Fortress may or may not be present in Twilight Princess. The Gerudos themselves have obviously deserted their desert homeland as they seem to be completely absent from the game (give or take a couple of key characters that tie in to the plot). This is of course, just a theoretical explanation as to why this area was seemingly omitted from Twilight Princess as it was very much present 100 years before in its predecessor, Ocarina of Time.

Another theory as to why it is absent from Twilight Princess is because in Ocarina of Time, Gerudo Valley was cut in to by Zora's River, and even though Zora's River runs somewhat close to the Gerudo Desert in Twilight Princess, it does not reach all the way, but rather breaks off at Lake Hylia. The similarity between the waterfall at Lake Hylia in Twilight Princess and the waterfall at Lake Hylia in Ocarina of Time is very similar in form, but because the geography has changed so much between the two games, it does not bare any relation with the Gerudo region of Hyrule. It makes one wonder if perhaps the Gerudo Valley was just entirely cut off from the rest of Hyrule because of a "jump" in the Zora's River.

Upon scrutinizing the map of Hyrule in Twilight Princess, one may see a "gap" between the land on the southern edges of Lake Hylia and the closest point that the Gerudo Desert comes in contact with the lake (due to it being the only landmass completely separated from the rest of Hyrule). Perhaps, the Gerudo Valley/Fortress is located within that non-explorable gap, and if so, do the Gerudo still inhabit their home? Again, just another theoretical attempt at finding the lost geographical connections between Ocarina of Time and Twilight Princess.

Trivia

 * In Ocarina of Time you are able to go to the Gerudo Valley as a child. You can do this by using a glitch that involves getting a Cucco and standing on a post and flying it across the broken bridge.