Marsh systems in Maine can generally be classified into three different types based on their overall geomorphology and shape. 

Back-Barrier Marshes Finger Marshes Fringe Marshes

  Located adjacent to barrier beaches, with direct access to the ocean through tidal inlets. Usually dominated by high marsh.

Long marshes along tidal channels. The area of high marsh is large compared to size of the channel.

Marshes on the edges of protected shorelines in estuarine coves and rivers, or at the toe of eroding bluffs. With less area of high marsh and bordered by mud flats, fringe marshes are strongly influenced by erosion from ice and waves.