The Avenue of the Giants is a scenic highway in Northern California, U.S.A., running through Humboldt Redwoods State Park. It is an old alignment of U.S. Route 101, and continues to be maintained by the state as State Route 254.

The southern entrance to the Avenue is just north of Garberville, and the northern entrance is south of Fortuna. The highway is notable for the Coast Redwoods that overshadow the road and surround the area. It is from these towering trees that the Avenue of the Giants takes its name. The road winds alongside the scenic Eel River, and connects several small towns such as Phillipsville, Miranda, Myers Flat, Burlington, Weott, Englewood, Redcrest and Pepperwood. The two-lane road has a number of parking areas, picnic sites, and attractions for visitors. The nearby river provides many excellent swimming locations, such as those at the Rockefeller Forest redwood grove.

Being situated just off a major highway, and having attained some degree of international fame, the Avenue has many attractions for visitors, both natural and human-made.

The route contains the site of the annual "Avenue of the Giants Marathon".

Though not the oldest redwood in the forest, this large tree is over 950 years old, and is currently around 250 ft (76 m) tall, though originally it was much taller. It has survived not only the ravages of time but also the 1964 flood of the area, a 1908 attempt at logging, and a direct lightning strike which removed the top 45 feet (14 m) of the tree (making its original height close to 300ft). It is from its age and the perceived hardiness to the fates that the tree derives its name. Markers are visible on the tree, denoting the heights of where the loggers' axes and the floodwaters struck the tree.

Situated in the northern half of the Avenue, The Immortal Tree is easy to find, and has a large gift shop and parking area in front of it.

Near Weott, this grove has an easy 1/2 mile self-guided walk with informational booklets available at the beginning of the trail. This well-travelled trail is a good example of old-growth redwood forest and contains a few very big trees, including the Founder's Tree (346 ft. tall) and the Dyerville Giant (~370 ft. tall) which fell down in 1991.

Avenue of the Giants features three trees in Northern California that visitors can drive through. The southernmost of these trees, Chandelier Tree, is located in Drive-Thru Tree Park in the town of Leggett. Shrine Drive-Thru Tree is near the town of Myers Flat and Klamath Tour Thru Tree, the northernmost of the three trees, is located in the town of Klamath, California. Each tree is privately owned and charges $5 or more to drive through.

Not a traditional tree house, this is actually a house that is, albeit partially, built within a giant redwood.

Visible from the road, and with tours available, the front of this house is entered through the hollow trunk of a still-living tree. The front door and windows are clearly visible to passers-by, and the rest of the house adjoins the rear of the tree in a more traditional style.

The Eel River is the third largest river in California. It carves deep canyons down great mountains, through flat valleys, and past majestic and ancient redwood forests. The Avenue of the Giants follows the South Fork of the river, but also features the branching of the South and Main forks to its north.

The Avenue of the Giants was part of U.S. Route 101 until a freeway bypass was completed in 1960, assuming the 101 designation. The Avenue was then designated as CA Route 254 by Assembly Concurrent Resolution 10.

Except where prefixed with a letter, postmiles were measured on the road as it was in 1964, and do not necessarily reflect current mileage. The entire route is in Humboldt County.