route 147 begins as middlefield road at an intersection with route 17 just north of the town center of durham. it heads northwest, crossing into the town of middlefield after , where the road changes name to durham road. within middlefield, it continues northwest, crossing the coginchaug river, to an overlap with route 157 (main street) about north of the town line, during which it heads north. after overlapping route 157 for , the two routes split with route 157 continuing northeast to middlefield center and the village of rockfall, and route 147 heading northwest as baileyville road to the village of baileyville towards the city of meriden. route 147 continues northwest and north for another until it ends at an intersection with route 66 in northwestern middlefield.