Merrimack Valley Federal Credit Union Belonging to a credit union has never been easier. And not only does membership provide you with the freedom to choose the very best in financial products and services, but it gives you ownership in the decisions made at Merrimack Valley FCU. Located in Haverhill, Methuen, Lawrence, North Andover, and Plaistow, NH.     Corporate Headquarters Call Center 500 Merrimack Street Lawrence, MA 01843   1-800-356-0067