Peachtree Corners is Gwinnett County’s newest city. Peachtree Corners is located to I-85, I-285 and GA 400, GA 400 and is just 30 minutes northeast of Atlanta. Founded on July 1, 2012, it is home to over 40,000 residents. The new city is 17 square miles in size and is located in the southwest corner of the county. Seven miles of the Chattahoochee River define its western border.