Sherman is the northernmost town of Fairfield County , Connecticut , United States . The population was 3,827 at the 2000 census. The town is named for New Haven 's famous Founding Father , Roger Sherman . The Appalachian Trail goes through the northern end of Sherman for 1 to 2 miles. Part of Squantz Pond State Park is in the town. Sherman has one area on the National Register of Historic Places: The Sherman Historic District, bounded roughly by the intersection of Old Greenswood Road and Route 37 , northeast past the intersection of Route 37 East and Route 39 North and Sawmill Road. The district was added to the National Register on August 31 , 1991 . The town is the only one in Fairfield County outside the "(203)" area code (it's in "(860)").