Question: Which county shares a border with the county where the most populous city in the state where Redan High School is located?

Knowledge 1: List of municipalities in Georgia (U.S. state)
The largest municipality by population in Georgia is Atlanta with 420,003 residents, and the smallest municipality by population is Edge Hill with 24 residents. The largest municipality by land area is Augusta, a consolidated city - county, which spans 302.47 sq mi (783.4 km), while Edge Hill and Santa Claus are tied for the smallest at 0.18 sq mi (0.47 km) each. [SEP] Knowledge 2: Sno*Drift
Sno*Drift is a rally racing event held in Montmorency County, Michigan, annually, with headquarters in Atlanta, Michigan. The event is currently the first Rally America National Rally Championship event of the season. Currently the event is organized into three distinct rallies: the national championship event covering both days of rallying, and two regional rally events each covering one of the two days. Competitors may be entered in any or all of these events simultaneously. [SEP] Knowledge 3: Redan High School
Redan High School is a public secondary school of the DeKalb County School District located in unincorporated DeKalb County, Georgia, United States. The school is south of the city of Stone Mountain. [SEP] Knowledge 4: Alpena Power Company
Alpena Power Company is a public utility company that provides electricity to most of Alpena County, Michigan, as well as southeastern Presque Isle County and the village of Hillman, in Montmorency County. The headquarters are located in Alpena, Michigan. The company was founded in 1881 by George N. Fletcher.
Knowledge 1: Redan High School
Redan High School is a public secondary school of the DeKalb County School District located in unincorporated DeKalb County, Georgia, United States. The school is south of the city of Stone Mountain. [SEP] Knowledge 2: List of municipalities in Georgia (U.S. state)
The largest municipality by population in Georgia is Atlanta with 420,003 residents, and the smallest municipality by population is Edge Hill with 24 residents. The largest municipality by land area is Augusta, a consolidated city - county, which spans 302.47 sq mi (783.4 km), while Edge Hill and Santa Claus are tied for the smallest at 0.18 sq mi (0.47 km) each. [SEP] Knowledge 3: Sno*Drift
Sno*Drift is a rally racing event held in Montmorency County, Michigan, annually, with headquarters in Atlanta, Michigan. The event is currently the first Rally America National Rally Championship event of the season. Currently the event is organized into three distinct rallies: the national championship event covering both days of rallying, and two regional rally events each covering one of the two days. Competitors may be entered in any or all of these events simultaneously. [SEP] Knowledge 4: Alpena Power Company
Alpena Power Company is a public utility company that provides electricity to most of Alpena County, Michigan, as well as southeastern Presque Isle County and the village of Hillman, in Montmorency County. The headquarters are located in Alpena, Michigan. The company was founded in 1881 by George N. Fletcher.
Knowledge 1: Redan High School
Redan High School is a public secondary school of the DeKalb County School District located in unincorporated DeKalb County, Georgia, United States. The school is south of the city of Stone Mountain. [SEP] Knowledge 2: List of municipalities in Georgia (U.S. state)
The largest municipality by population in Georgia is Atlanta with 420,003 residents, and the smallest municipality by population is Edge Hill with 24 residents. The largest municipality by land area is Augusta, a consolidated city - county, which spans 302.47 sq mi (783.4 km), while Edge Hill and Santa Claus are tied for the smallest at 0.18 sq mi (0.47 km) each. [SEP] Knowledge 3: Sno*Drift
Sno*Drift is a rally racing event held in Montmorency County, Michigan, annually, with headquarters in Atlanta, Michigan. The event is currently the first Rally America National Rally Championship event of the season. Currently the event is organized into three distinct rallies: the national championship event covering both days of rallying, and two regional rally events each covering one of the two days. Competitors may be entered in any or all of these events simultaneously. [SEP] Knowledge 4: Tennessee
Tennessee (i/tɛnᵻˈsiː/) (Cherokee: ᏔᎾᏏ, Tanasi) is a state located in the southeastern United States. Tennessee is the 36th largest and the 17th most populous of the 50 United States. Tennessee is bordered by Kentucky and Virginia to the north, North Carolina to the east, Georgia, Alabama, and Mississippi to the south, and Arkansas and Missouri to the west. The Appalachian Mountains dominate the eastern part of the state, and the Mississippi River forms the state's western border. Tennessee's capital and second largest city is Nashville, which has a population of 601,222. Memphis is the state's largest city, with a population of 653,450.

Answer: Presque Isle County