The Grand Canyon is a steep-sided canyon carved by the Colorado River in Arizona, United States, and is one of the many natural wonders of the U.S. It is eighteen miles (29 km) wide in some places, 220 miles (350 km) long, and plunges to depths of 5,970 - 6,000 ft (1,800 - 1,820 m). It is mostly contained within the Grand Canyon National Park, one of the first national parks in the United States. It has a viewing platform shaped as a U.
Jason Grace, Piper McLean, and Leo Valdez visit the Grand Canyon on a Wilderness School field trip. While doing a worksheet on the observation platform, the three demigods and their protector Gleeson Hedge are attacked by Dylan, a ventus in disguise, by the sorceress Medea's orders. Leo is thrown off the bridge by Dylan and saved by Coach Hedge, who, being a satyr, is able to climb down the canyon wall thanks to his goat hooves. Meanwhile, Jason distracts the venti with his sword Ivlivs. Piper is also thrown off the bridge and into the canyon, but Jason saves her by jumping over the sky-walk to save her, using his powers over air to control the currents. After Dylan escapes with Hedge, Annabeth Chase and Butch arrive and take them to Camp Half-Blood.
- The Grand Canyon Skywalk was built near a natural rock formation known as Eagle Point, because it looks like an eagle taking flight. As the eagle is the symbol of Zeus/Jupiter, it is likely not a coincidence that this would be where Hera/Juno chose to wake Jason up.