Do you have the area for each census tract? The DC/Balt area is pretty large, stretching from Winchester and WV through to Baltimore, Annapolis, and Southern Maryland.
I recently learned that I don't live in the DC Metro area anymore.
They actually designated Berkeley County, WV and Washington County, MD as their own metro area now. It's the Hagerstown/Martinsburg Metropolitan Area. I believe Winchester, VA, Charlestown, WV, and Harpers Ferry, WV are still in the DC metro area though.