Maryland Abbreviation: MD and Md.

Maryland abbreviation at a glance

Those capital pairs date from the 1960s, when the post office wanted short state codes that sat neatly beside the new ZIP codes. That history is also why they never take periods.

MD state abbreviation for mail and forms

MD is the official postal abbreviation and the one sorting machines expect. Type both letters as capitals, skip the period, and follow with the ZIP code. Maryland ZIP codes start with 20 or 21, so a Maryland address will typically end with a five-digit number in that range.

On drop-down menus in online forms, Maryland is listed under MD, usually between Maine (ME) and Massachusetts (MA) if the list is sorted by name, or between MA and ME if sorted by code.

When to use Md. instead

Md. is the traditional abbreviation of Maryland, the style that was common before the postal codes existed. You will still see it in a few places:

• News datelines: AP style uses Md. after a city name at the start of a story, as in "BETHESDA, Md."
• Older books and documents: footnotes, letters and records often use Md.
• Some lists and tables where a full name will not fit but a postal code feels too technical.

Inside the text of an article, AP style uses the whole word Maryland. Most writing guides give the same advice for essays, reports and business letters: write "Maryland," not MD or Md., in running text.

Do not mix up MD with these M codes

Eight states start with M, and their codes are easy to confuse. Maryland is MD, for the M and the D in Maryland. The others:

• Massachusetts is MA
• Maine is ME
• Michigan is MI
• Minnesota is MN
• Missouri is MO
• Mississippi is MS
• Montana is MT

A common slip is writing MA for Maryland. MA belongs to Massachusetts, so a letter marked MA with a Maryland ZIP code sends mixed signals and can slow delivery.

Other things MD can mean

These letters also turn up in other settings, which is why people sometimes search for a "Maryland acronym" and find something else.

• Medicine: MD after a name means Doctor of Medicine, as in "Dana Ruiz, MD."
• Business: MD can mean managing director, a senior job title.
• Washington area: MD often appears next to DC and VA, as in the "DMV" region nickname for D.C., Maryland and Virginia.

If MD follows a city name or sits before a ZIP code, it is the state. If it follows a person's name, it is a medical degree.

A few Maryland facts that help with addresses

Maryland's capital is Annapolis, and its largest city is Baltimore. The state was named after Queen Henrietta Maria, wife of King Charles I of England, and one of its nicknames is the Old Line State. It borders Pennsylvania, Delaware, Virginia, West Virginia and Washington, D.C., so many Maryland residents cross state lines for work and see MD, VA and DC side by side on forms every day.

For the codes of every state, see the full state abbreviations chart.