Boulder Garden Loop Trail and Mount Si Old Trail

Starting your adventure near King County, Washington, the Boulder Garden Loop Trail and Mount Si Old Trail offer a challenging yet rewarding experience. The trailhead is conveniently located near the Little Si Trailhead, which can be accessed by car or public transport. If driving, take I-90 East from Seattle and exit at 32 for 436th Avenue SE. Follow SE North Bend Way and turn onto Mount Si Road. Parking is available at the Little Si Trailhead. For public transport, King County Metro Transit provides bus services to North Bend, where you can catch a local taxi or rideshare to the trailhead.

### Trail Overview

The loop spans approximately 10 km (6.2 miles) with an elevation gain of around 1200 meters (3937 feet). This trail is rated as medium difficulty, making it suitable for hikers with some experience and a good level of fitness. The trail combines the Boulder Garden Loop with the Mount Si Old Trail, offering a diverse range of landscapes and challenges.

### Key Sections and Landmarks

#### Boulder Garden Loop

Starting from the Little Si Trailhead, the initial section of the trail takes you through dense forest, characterized by towering Douglas firs and Western hemlocks. About 1.5 km (0.9 miles) in, you'll encounter the Boulder Garden, a fascinating area filled with large moss-covered boulders. This section is relatively flat, providing a gentle warm-up before the more strenuous ascent.

#### Mount Si Old Trail

After completing the Boulder Garden Loop, you'll merge onto the Mount Si Old Trail. This is where the real climb begins. The trail becomes steeper and more rugged, with switchbacks that will test your endurance. Approximately 4 km (2.5 miles) from the trailhead, you'll reach Snag Flats, a small plateau offering a brief respite and a chance to catch your breath. This area is named for the numerous tree snags, remnants of past forest fires.

### Flora and Fauna

The trail is rich in biodiversity. Keep an eye out for black-tailed deer, Douglas squirrels, and a variety of bird species including the Pacific wren and the Steller's jay. The flora changes with elevation; lower sections are dominated by ferns and salal, while higher elevations feature huckleberry bushes and wildflowers in the spring and summer.

### Historical Significance

Mount Si holds cultural significance for the Snoqualmie Tribe, who consider it a sacred site. The mountain is named after Josiah "Uncle Si" Merritt, an early settler in the region. The old trail itself has historical roots, having been used by loggers and miners in the late 19th and early 20th centuries.

### Navigation and Safety

Given the trail's complexity, it's advisable to use a reliable navigation tool like HiiKER to keep track of your progress and ensure you stay on course. The trail can be muddy and slippery, especially after rain, so sturdy hiking boots with good traction are essential. Carry plenty of water, snacks, and a first-aid kit. Weather can change rapidly, so layers and rain gear are recommended.

### Reaching the Summit

The final push to the summit is the most challenging, with steep, rocky sections that require careful footing. Once you reach the top, you'll be rewarded with panoramic views of the Snoqualmie Valley, the Cascade Range, and on clear days, even the Seattle skyline. The summit area is exposed, so be prepared for wind and cooler temperatures.

Descending via the same route, take your time to navigate the steep sections safely. The entire hike can take anywhere from 5 to 7 hours, depending on your pace and the time spent at various points of interest.