State Route 166 (SR 166) is a state highway in the U.S. state of Georgia. It connects the Alabama state line with the city of Atlanta. The highway travels through Carrollton, McWhorter, and East Point. Except for the Carrollton and East Point/Atlanta areas, the highway is fairly rural. In Atlanta, it has a limited-access freeway portion that is known as the Arthur B. Langford Jr. Parkway (formerly named the Lakewood Freeway).