Directions to the Allatoona Lake Project Management Office: From I-75 take Exit 290 and go east on GA Highway 20. Take the first right at the light for GA Highway Spur 20. Proceed on Spur 20 approximately 4 miles until the end of the road and you see signs indicating Project Management Office. Turn right through the gate and proceed up the hill to the office. Office Hours: 8:00 am - 4:30 pm.