 From this point on, the Naugatuck River has been followed by early paths and roadways, through the time of development of Connecticut Route 8.The river enters a forested, hilly area between Connecticut Route 118 and Thomaston.The largely industrialized cities of the Naugatuck River Valley were developed on each side of the river, with periodic sections of forested areas, before it enters the Housatonic River at Derby, at about above sea level.