What is the routing number for landmark credit union? LANDMARK CREDIT UNION ROUTING ABA NUMBER. 275079714 routing number is a 9-digit number designed and assigned to Landmark Credit Union by The American Bankers Association (ABA) to identify the financial institution upon which a payment was drawn.Where is landmark credit union headquarters? Landmark Credit Union was chartered on June 28, 1940. Headquartered in North Adams, MA, it has assets in the amount of $26,453,880. Its 2,761 members are served from 1 location.What is credit union marketing? AGP Digital Marketing. AGP Digital Marketing is a credit union marketing agency specializing in web design and development, marketing campaigns and strategy, business development, video marketing, graphic design, copywriting, public relations and video production.