Industrial complexes and office parks sprung up in Clayton in the 1980's and 1990's. These are strategically located nearby airport facilities, rail lines and trucking routes. Major employers in the county include: Delta Airlines, Inc., J. C. Penney Distribution Center, Southern Regional Medical Center, Southlake Mall, Northwest Airlines, Georgia Department of Revenue and the U.S. Army at Fort Gillem.
In keeping with its farm background, one of the world's largest Farmers Markets is located in the northern section of the county, in Forest Park. The 143 acre Market boasts numerous wholesale dealers and a shed area where Georgia farmers daily display and sell fresh farm produce to market visitors.
In 1975 Southlake Mall opened in Morrow, establishing a retail complex of over 100 stores. In the late 1990's, the Mt. Zion corridor was developed bringing in many more retail stores and restaurants.