Membership is open to residents of several Indiana counties (including most of the Indianapolis metro area). You can also qualify based on select employer groups and family. I wasn't able to find their membership page, but I did find this Q&A page with some more details. Membership requires a minimum deposit of $5 into a savings account.
Branches are located in Indianapolis, Avon, Fishers, Noblesville, and Carmel. The credit union is federally insured by the NCUA (Charter # 68248). It has $992.3 million in assets and 95,649 members.