The paper mills have closed, the towboats are gone, and the river drivers who used to ride and guide logs down Maine’s white-water rivers to lakes and on to mills are only a memory, but the Ambajejus Boom House survives. Constructed in 1906 at the mouth of the West Branch of the Penobscot, this, like other boom houses, was a rest stop for the river drivers. Former river driver Chuck Harris meticulously restored this once-derelict building, now listed on the National Register of Historic Places, and filled it with artifacts. Access is by canoe from Spencer Cove (hug the shoreline to avoid wind gusts and choppy water); via guided trips with the Big Moose Inn or New England Outdoor Center; or by snowmobile in winter.