Arsenal Credit Union was founded in August 1948 as Aero Chart Credit Union and organized to serve employees of a U.S. government agency then known as the Aero Chart Service, Plant and Store (now the National Geospatial-Intelligence Agency, or NGA). The name changed to Arsenal Credit Union in 1952,^[1] a tribute to what NGA's current campus, along the banks of the Mississippi River in south St. Louis, used to be known as the "St. Louis Arsenal" back in the country's Civil War days. During this time, the site had warehoused small arms, artillery, gun carriages, ammunition and gunpowder.^[2]

In Missouri, membership is open to those who live or work in St. Louis County, Jefferson County, Franklin County, Washington County, St. Francois County, and Ste. Genevieve County. The credit union also offers membership in Illinois, which is available to those who live or work in St. Clair County, Madison County, Monroe County, and Randolph County. Arsenal also serves those who live or work in select ZIP codes in Jasper County (64801), Miller County (65026), Camden County (65049 & 65065), and Morgan County (65072) in the state of Missouri. Those who have a parent, grandparent, brother, sister, child, grandchild, spouse, aunt, uncle, niece, nephew, first cousin or legal guardian who is eligible to be an Arsenal member can join through them. This includes steps, in-laws and legally adoptive relationships.^[3]

Those employed by or who have retired from the NGA, and those who work for the Department of Veterans Affairs (Veterans Administration) are also eligible to join. Those who belong to the following labor organizations can join the credit union:

• Bakers, Confectioners, Tobacco Workers and Grain Millers (BCTGM) Local 4
• Communication Workers of America (CWA) 4217
• Iron Workers Local 396
• Service Employees International Union (SEIU) Healthcare Illinois
• United Food and Commercial Workers (UFCW) Local 534

Arsenal Credit Union has four public locations in the following St. Louis metro areas: Arnold, Webster Groves, Florissant, and in Swansea, Illinois. In addition, the credit union has an Interactive Teller Machine (ITM) at NGA's South 2nd Street location for use by people who have access to the military base.

Arsenal is part of the Credit Union Shared Branch network, which gives members the ability to transactions on their Arsenal accounts at more than 70 other credit union shared branch locations in the St. Louis metro area and more than 5,800 nationwide.^[4] It is also a member of the CO-OP Network of ATMs, which gives members free access to more than 250 ATMs in the St. Louis area and 30,000 nationwide.^[5]

Arsenal Credit Union offers a full complement of loans, deposit accounts and convenience services for its members. It also offers unique products not available from most financial institutions.

• A Totally Free Checking account with no monthly maintenance fees or monthly minimum balance requirements
• Instant-issue debit cards available at its four public branches
• A Spend to Save program that rounds up a debit card holder's transactions to the nearest dollar amount and automatically deposits the change into their savings account at the credit union
• Live Video Banking
• Home equity loans with a 100 percent financing option
• Go Green loans for environmentally friendly home repairs

In addition to consumer services, Arsenal offers loans and deposit accounts for local small businesses.

Since 1997, Arsenal has been helping students reach their financial goals with a college scholarship program. The credit union has awarded a total of $109,150 to 107 students.

As part of its mission of "people helping people," Arsenal runs a Community Impact Fund. Nonprofit organizations in the credit union's field of membership are eligible to apply for grants from this fund during open registration periods. Since 2020, the credit union has awarded $44,800 to over 20 nonprofit organizations.