Health-General Article, 13-3304(g)(5) establishes that a qualifying patient or caregiver may only obtain medical cannabis from a medical cannabis grower or dispensary licensed by the Maryland Medical Cannabis Commission.
In addition, the statutory protections from arrest, prosecution, or any civil or administrative penalty established in Health-General 13-3313 only extend to those patients and caregivers who act in accordance with Maryland law, which includes obtaining cannabis from a medical cannabis grower or dispensary licensed by the Commission. Individuals obtaining cannabis from other jurisdictions are not protected under the statute, and may be subject to arrest, prosecution, or civil or administrative penalties from state or local law enforcement in Maryland.
What this means... even though DC dispensaries will happily let you into their dispensaries, you will be breaking Maryland law if you try and bring marijuana back into Maryland. Apparently there are some sheriff offices in some Maryland counties that are taking this very serious. Please be mindful.