SR 27 begins at SR 238 in Southport and heads northeast to the town of Boothbay Harbor. It intersects SR 96, then heads north to the town of Edgecomb to US 1, where it turns left along US 1 heading into the town of Wiscasset. It intersects SR 218, and then immediately turns right and continues north to Dredsen, where it intersects SR 197. SR 27 continues north to Pittston where it intersects State Route 194 and State Route 126. SR 27 continues into Randolph where it intersects SR 226 and then turns west as SR 9 continues north to Augusta.