MedMark Treatment Centers Mt. Vernon is an addiction treatment center located at 817 N Calvert St, Baltimore, MD 21202. We offer a range of services focused on recovery and support. Our facility is open Monday through Friday from 5:30 AM to 1 PM, Saturday from 6:30 AM to 10:30 AM, and closed on Sundays. For more information, you can reach us at +14108169339 or visit our website at medmark.com.