Inside Passage, natural protected waterway, northwestern North America, 1,500 km (950 mi) long. It extends along the coast from Seattle, Washington, to Skagway, Alaska, and is an important year-round shipping lane. The passage is made up of a series of straits sheltered from Pacific Ocean storms by Vancouver Island and other islands. Ports along the passage include Vancouver and Prince Rupert, B.C., Canada, and Ketchikan, Wrangell, and Juneau, Alaska.