Lawrenceville Depot Lawrenceville's former Seaboard Air Line Railway depot now houses local businesses. (At Clayton and Depot Streets north of downtown.) The county seat of Gwinnett County in northeast metro Atlanta, Lawrenceville was long a small town but has grown rapidly to its current population of 25,000.     Georgia's Railroad History & Heritage. Copyright, Steve Storey. Railroad History | The Depot List | Locomotives On Display | Odds & Ends | Sources & References | Home