D.C. code
7-2509.07 states no person holding a license shall carry a pistol in the following locations or under the following circumstances:
A municipal building including any adjacent parking lot, of an childcare facility, preschool, public or private elementary or secondary school; or a public or private college or university; A hospital, or medical or mental health services office; A penal institution, or halfway house; A polling place while voting is occurring; A public transportation vehicle; Any premises, or portion thereof, where alcohol is served.
