On the Southwestern Oregon Coast lies Coos Bay. Home to the Hanis and Miluk peoples, Coos Bay is a rich area of linguistic diversity. The languages of the Hanis and Miluk people, hanis kuukwiis (Hanis) and miluk kuukwiis (Miluk), have had their relationship described in a number of different ways. Early workers with Hanis described both languages as dialects of the ‘Coosan’ language, with Hanis being the principal dialect and Miluk being nearly mutually unintelligible. Others have described Hanis and Miluk as being mutually unintelligible and with Miluk having distinct dialects of its own. Still others have tried to link the languages to Oregon Coast Penutian and the Penutian Hypothesis and to the Salishan language family. The Hanis and Miluk people have long held that their languages and their peoples are related but distinct, though they are now confederated together by the United States government. This work seeks to tackle this issue of relatedness between Hanis and Miluk by utilizing the comparative method to provide evidence in support of Proto-Coosan and the Coosan language family.