Seattle Underground

The Seattle Underground is a network of connected passages and basement spaces located beneath the current street level in the Pioneer Square district. The system extends across several blocks and preserves the original architecture from the city's early days.

The network formed after the Great Fire of 1889, when Seattle rebuilt its streets one to two stories higher to address flooding issues. The old sidewalks and storefronts remained below the new level, creating this hidden layer.

The tours tell stories of early settlers dealing with mudflats, shops that once operated at street level, and the day-to-day challenges before the rebuild. Visitors see old storefronts, doorways, and remnants of signage that disappeared below ground after the reconstruction.

Tours begin at 614 First Avenue and last about 75 minutes. Comfortable shoes are recommended since the floors are uneven and the lighting is irregular, as the passages have not been fully modernized.

In some spots, you can still see the small glass blocks that once brought daylight into the basements. These vault lights now sit beneath the modern sidewalks and cast light patterns on the old pathways below.

Location: Seattle

GPS coordinates: 47.60200,-122.33400

Latest update: December 12, 2025 17:29