There are 13 US Post Offices in Strafford County serving a total of 112,115 residents equating to 8,624 residents per post office. It's estimated that approximately 178,948 packages are handled across the 13 county post offices annually. Strafford County is a county in the U.S. state of New Hampshire. As of the 2010 census, the population was 123,143. Its county seat is Dover. Strafford County was one of the five original counties identified for New Hampshire in 1769. It was named after William Wentworth, 2nd Earl of Strafford in the mistaken belief that he was the ancestor of governor John Wentworth. Although they were distantly related, William had no descendants. The county was organized at Dover in 1771. In 1840 the original size of the county was reduced with the creation of Belknap County. Strafford County is included in the Boston-Cambridge-Newton, MA-NH Metropolitan Statistical Area."