Downtown Seattle in King County, Washington — The American West (Northwest)

Ever-Changing Landscape

Photographed by Douglass Halvorsen, February 20, 2026

1. Ever-Changing Landscape Marker

Inscription. Elliott Bay and the land surrounding it was shaped over millennia by glaciers, volcanic eruptions, and earthquakes. More recently, humans have played a big part. The natural forces that have made this place so beautiful also pose risks, reminding us that our local landscape is a work in progress.

A Glacier’s Footprint

Why Seattle is So Steep
The Puget Sound was gouged out during the Ice Age by rivers running beneath the Puget Lobe, part of an ice sheet whose peak thickness over Seattle equaled the height of five Space Needles. The ice also shaped the surrounding land, furrowing it like a giant rake. The parallel ridges left behind are the hills of Seattle, which run north-south and tend to be steeper on their east and west sides.

What’s in the Hill?
Seattle’s hills are big piles of glacial sediment compressed by the glacier itself. They consist of three layers: clay at the bottom, sand and silt in the middle, and a thinner layer of rubble on top.

The Puget Lobe was the southernmost extension of continental glaciation and reached its maximum extent to the south around 16,000 years ago.

A Mountain’s Fury

Blowing its Top
The

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landscape around Elliott Bay wasn’t formed by ice alone. Many of its defining features were created by a series of eruptions of Mount Rainier (tǝqwuʔmǝʔ) starting 5,600 years ago. The first blew almost 1,600 feet off the top of the mountain, triggering a lahar—a cascade of water, ice and rock that sped down the mountain at 130mph. More eruption and lahars followed over the centuries, slowly filling in an arm of Puget Sound that stretched nearly to present-day Auburn and creating the Duwamish River Valley.

A Serious Shake-up

Seismic Shifts
An earthquake was the third force that shaped Elliott Bay. About 1,100 years ago, a magnitude 7 quake thrust up the ground at the Duwamish River delta by 20 feet. The quake was caused by movement along the Seattle Fault, which runs from Bainbridge Island through the southern end of downtown and east to about Issaquah. Scientists expect a major quake along the fault again. They just don't know when.

A Tide Gone By

Tidelands Tamed
Over thousands of years, lahars from Mount Rainier created the valley of the Duwamish River and nudged the river’s mouth some 30 miles northwest

Photographed by Douglass Halvorsen, February 20, 2026

2. Ever-Changing Landscape Marker

to where Seattle’s settlers found it, with a wildlife-rich tideflat stretching from West Seattle to Beacon Hill. Changes made by non-Native settlers as they built a city on the bay have transformed the Duwamish delta.

Dredging, filling, and other efforts undertaken by settlers for flood control, maritime navigation and commercial development have erased the tideflats (including sites long sacred and vital to local Indigenous people). This converted the southern waterfront to a center of economic activity.

Efforts are underway to clean up the river, restore some of the wildlife habitat, and make it a place where Native people can again gather.

Topics. This historical marker is listed in these topic lists: Environment • Natural Features.

Location. 47° 36.069′ N, 122° 20.179′ W. Marker is in Seattle, Washington, in King County. It is in Downtown Seattle. It is on Alaskan Way South, on the right when traveling south. Touch for map. Marker is at or near this postal address: 199 Alaskan Way S, Seattle WA 98104, United States of America. Touch for directions.

Regionally, this

Photographed by Douglass Halvorsen, February 20, 2026

3. Ever-Changing Landscape Marker

marker is in Washington’s Puget Sound Region.

It is also on the American Pacific Coast,

in the Pacific Northwest,

and in the Lewis & Clark Corridor.

Globally, it is in North America,

in the Cascade Range,

in the Inside Passage,

on the Ring of Fire,

on the Pacific Rim,

in the Western Hemisphere,

in the Western World,

and in the Anglosphere.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Chun Ching Hock (a few steps from this marker); Habitat Beach (a few steps from this marker); Who Belongs Here? / Violence & Vitriol (within shouting distance of this marker); Ballast Island (within shouting distance of this marker); Who landed here? (within shouting distance of this marker); Pioneer Square Hotel (about 300 feet away, measured in a direct line); What was Yesler’s Way? / How did a parking garage spark a preservation movement? (about 300 feet away); Maynard Building (about 400 feet away). Touch for a list and map of all markers in Seattle.

Other markers no longer nearby. Steamer Idaho Wreckage (was within shouting distance of this marker but has been permanently removed);

Photographed by Douglass Halvorsen, February 20, 2026

4. Ever-Changing Landscape Marker

Indians Attack Seattle! Jan. 26, 1856 (was within shouting distance of this marker but has been permanently removed); Seattle’s First Pier (was within shouting distance of this marker but has been permanently removed).

Photographed by Douglass Halvorsen, February 20, 2026

5. Ever-Changing Landscape Marker

View of marker looking south towards the historic boat landing pergola.

Credits. This page was last revised on September 16, 2026. It was originally submitted on September 14, 2026, by Douglass Halvorsen of Klamath Falls, Oregon. This page has been viewed 10 times since then. Photos: 1, 2, 3, 4, 5. submitted on September 14, 2026, by Douglass Halvorsen of Klamath Falls, Oregon. • Andrew Ruppenstein was the editor who published this page.