While Hawaii and Alaska are obviously non-contiguous with the rest of the US, Michigan is the only state in the contiguous 48 that consists of two large, completely separate landmasses: the Upper Peninsula and the Lower Peninsula. They are separated by the Straits of Mackinac, which connect Lake Michigan and Lake Huron. Until the Mackinac Bridge was completed in 1957, the only way to travel between the two parts of the state was by ferry or by driving through the neighboring states of Indiana, Illinois, and Wisconsin. The Upper Peninsula (the 'U.P.') is more geographically and culturally similar to northern Wisconsin, yet it remains an integral part of Michigan due to a 19th-century border dispute over the city of Toledo.