Founded in 1941 as a source of loans and basic savings products, GCS Credit Union has always focused on the member. Through the years, that philosophy has served us well, helping us grow from a single office in Granite City to a full-service financial institution serving Illinois counties: Sangamon, Logan, Macon, Marion, Jefferson, Perry, Jackson, Williamson, Jersey, Macoupin, Montgomery, Madison, Bond, Clinton, St. Clair, Monroe, Washington and Randolph. Anyone who lives, works, or attends school within these counties is eligible for GCS membership.