Mattawamkeag River: Mattawamkeag Wilderness Park to Lower Gordon Falls Professional Review and Guide
"The Mattawamkeag is Maine’s longest undammed river, but it usually runs throughout the summer on natural flow due to its very marshy watershed. It flows through a wilderness park that is classic backwoods Maine, and its rapids are interesting, though not as plentiful or as difficult as such better-known Maine classics as the Kennebec, Penobscot, and Dead.
Like the Penobscot, the Mattawamkeag is pool-drop, with several long stretches of flatwater in the 3.5-mile run. Each rapid is no more than a quarter-mile long, and all but one is a straightforward wave train at low to medium levels."