If you live in Maryland, USA you can get a Pre-registration for Covid19 Vaccine. Click this link to find your County and fill up a form. www.findmygroup.nc.gov Or
I tried to get an appointment thru the links provided by Montgomery County Gov site but all the places around 25 miles were booked for the NEXT 3 WEEKS!. And there is not an option to make an appointment for a later date.
After some investigating, I found the link at WTOP News Channel 9.
The link above helps you fill up a form answering 6 questions, then you will have a Pre-Registration form. You will be contacted via email or cell phone to make your actual appointment.