Chapter membership is separate and distinct from IIBA central membership. We are working on a way to integrate these. If you have never been an IIBA member, give a trial membership an try; it's a great way to be an active chapter member for the trail period (one year) without having an IIBA central membership. At the end of the triall period, we hope you join the IIBA and continue as a member of our chapter.
If you are already an IIBA member, we have a Baltimore and DC as well as DC-only chapter memberships available.