Citadel Credit Union | 6,341 followers on LinkedIn. Building Strength Together | Established in 1937, Citadel is a not-for-profit, member-owned credit union serving Greater Philadelphia. For over 80 years, we’ve delivered a breadth of financial services, expert guidance, and innovative tools to help strengthen and grow businesses, families, and our local communities. Our members are the foundation of who we are – driving our purpose each and every day.