How The Puget Sound Came to Be

Have you ever wondered what the Pacific Northwest region we call home looked like long before human beings existed? Or how the landscapes of this area came to be?

Long before our existence, wooly mammoths, saber-toothed cats, as well as dinosaurs once grazed the land we live on. In the early 1900s, a scientist named Harlan Bretz suspected that ice was to blame for today's labyrinth of waters— lakes, channels, inlets, bays, and streams. Bretz surmised that about 17,000 years ago, a massive glacier bulldozed its way south from Canada to lie across our region. The ice rose 3,000 feet—so deep that it nearly covered the Olympic and Cascade peaks on either side. Its most significant feature lay underneath, however: loads of gravel, rocks and boulders, natural grinding tools that reshaped the terrain below.

Before the big thaw began, the glacier pushed all the way down to Olympia. Then, once the thaw began, the ice began a gradual retreat, leaving what is now the Puget Sound- as well as many other fresh and saltwater byways.

Over the next few thousand years, the Pacific Ocean slowly took over parts of our region as the large glacier melted: which is now what we call the Strait of Juan de Fuca. Another giant gouge, stretching northward, filled in to become the Strait of Georgia, up north in British Columbia. Combined with the Puget Sound, these three bodies of water are now known as the Salish Sea—named after the Salish people who navigated these shores before 1791.