Seattle ( (3) In 1851, a large party led by Luther Collins made a location on land at the mouth of the Duwamish River; they formally claimed it on September 14, 1851. Thirteen days later, members of the Collins Party on the way to their claim passed three scouts of the Denny Party, the group who'd eventually found Seattle. Members of the Denny Party claimed land on Alki Point on September 28, 1851. The rest of the Denny Party set sail from Portland, Oregon and landed on Alki point during a rai… (More on Seattle)