Killen is a town in Lauderdale County, Alabama, United States. It is part of the Florence - Muscle Shoals Metropolitan Statistical Area known as "The Shoals". As of the 2010 census, the population of the town is 1,108. Killen Founder's Day is an annual event celebrated either on the third or fourth weekend in the month of August. The festivities begin on Friday at 6:00 p.m. with a parade through downtown Killen on JC Mauldin Hwy starting at Brooks Elementary School and ending at the Market Center. Opening ceremonies are held at 7:30 at Killen Park in our amphitheater.