  frankfort is a town on the penobscot river estuary in waldo county, maine, united states.delorme mapping company the maine atlas and gazetteer (13th edition) (1988) isbn 0-89933-035-5 map 23 the population was 1,124 at the 2010 census. ==history==  frankfort is the oldest town on the penobscot river, first settled in the 1760s by massachusetts soldiers from nearby fort pownall. with the end of the french and indian war, the penobscot valley became part of new england, and more specifically massachusetts, leading to the first cautious encroachments by english-speaking settlers on the lands of the penobscot indians. this process, which would begin in frankfort, would end with the founding 
Towns_in_Maine Towns_in_Waldo_County,_Maine