Michigan. Actually it's Alaska. Michigan is second.
Florida.
The longest coastline of a state in the US is Alaska but the longest continental coastline of a state in the US is Florida.
Mount St. Helens (May 18, 1980) in southwest Washington state is the most recent volcanic eruption in the continental US. In Hawaii, Mauna Loa has erupted more recently (1984) and Mount Kilauea has continued to erupt since 1993.
California is the most noticeable US state that has a transform boundary.
Alaska has the longest shoreline of any US state by far.
Michigan has 3288 miles of shoreline (Great Lake Shoreline), most of any state other than Alaska.
Alaska is the state with the most shoreline because it includes many islands and the state itself is enormous. Behind that would probably fall California and Florida.
maine
maine
Florida
Hawaii
Mississippi
Kansas
Rohde Island is the smallest continental US state
The state of Minnesota has more than 90,000 miles of shoreline. This is more than the states of Florida and California.
Alaska is the most northernly state in the continental and all of the USA. Minnesota is the most northernly state in the contiguous USA.