Mueller Tunnel via Loma Alta Trailhead

The hike typically starts from the vicinity of Loma Alta Drive in Altadena. A common access point is the trailhead for the Sam Merrill Trail, located at the intersection of Lake Avenue and Loma Alta Drive. Be aware that an Adventure Pass from the National Forest Service may be required for parking in some areas within the Angeles National Forest.

This route is considered difficult, involving significant elevation gain (over 1200 meters) and a distance of nearly 13.5 kilometers. The initial ascent on trails like the Sam Merrill Trail involves steady inclines and switchbacks. While the immediate area around Mueller Tunnel itself might be less steep, the overall journey from Loma Alta Drive is a strenuous endeavor.

The hike is located within the Angeles National Forest, which is part of the San Gabriel Mountains National Monument. While there isn't a specific entrance fee for hiking, an Adventure Pass may be required for parking at some trailheads. You can purchase these passes at ranger stations or authorized vendors.

Yes, dogs are generally allowed on trails within the Angeles National Forest. However, they must be kept on a leash at all times to protect wildlife and ensure the safety of other hikers. Always remember to pack out any waste.

Spring and fall generally offer the most pleasant hiking conditions with milder temperatures. On clear days, you'll get the best panoramic views. Summer can be very hot, so if hiking then, start early and carry plenty of water. Winter can bring colder temperatures and occasional snow at higher elevations, so check conditions before you go.

The terrain varies. You'll start with well-maintained trails like the Sam Merrill Trail, known for its switchbacks. As you ascend, you'll encounter oak woodlands and chaparral. Sections of the route, particularly along the Mt Lowe gravel road, can be rocky and pass through areas that have re-vegetated after wildfires.

The hike offers diverse scenery. From lower elevations, you'll get expansive views of the Los Angeles Basin, and on clear days, you might even spot the ocean. As you climb, enjoy panoramic vistas of the San Gabriel Mountains, including Mount Wilson. The highlight is undoubtedly the Mueller Tunnel itself, a unique historical landmark cut into the mountain.

Yes, the route to Mueller Tunnel from Loma Alta Drive utilizes and intersects with several trails. You'll likely start on the Sam Merrill Trail, and the route eventually merges with sections of the Mount Lowe Motorway. Other official trails in the area include the Altadena Crest Trail, Chaney Trail, and Tom Sloan Trail.

Mueller Tunnel was blasted through the mountain in 1942 by the U.S. Forest Service. It was part of a fire road system and served as a gateway to Mount Lowe, which was a popular tourist destination accessible by an incline railway in the early 20th century. After a landslide in 2009, it was closed to motor vehicles, preserving it as a unique hiking and cycling destination.

Given the trail's difficulty and mountainous terrain, be prepared for steep drop-offs in certain areas. Poison oak can also be present, so it's wise to know how to identify it. Always carry plenty of water, especially on warm days, and be mindful of changing weather conditions in the mountains.

While this specific route starts from Loma Alta Drive, some hikers access Mueller Tunnel from Eaton Saddle Trailhead. This approach can significantly shorten the hike to the tunnel itself, making it a less strenuous option, though it requires driving further up into the mountains to reach that trailhead.