Concord is the capital of the state of New Hampshire in the United States. It is also the county seat of Merrimack County. As of the 2000 census, its population was 40,687. In July 2006, it had an estimated population of 42,378. Concord apartments for rent comparison page shows most up to date rent information on Concord apartments and houses. Rent information is obtained from multiple rental sources but we cannot guarantee their accuracy.