Students and teachers come from the entire Washington, D. C. metropolitan area, including Montgomery, Prince George's, Charles, Howard, Baltimore, Ann Arundel and Calvert counties in Maryland, the District of Columbia, and Northern Virginia.

They originate from North, South and Central Americas, Iceland, Asia, the Pacific Islands, the Middle East, several countries in Africa, Europe, the Ukraine and the Caribbean.

During the summer, the OMS Camps and Institutes include students from various states of the union, and the Caribbean. In 2008 they came from New York, New Jersey, North Carolina, and Florida. In 2006 and 2007 besides those states there were people from Trinidad (12) and the U. S. Virgin Islands.

• 36% Prince George's County, Maryland
  
• 28 Montgomery County, Maryland
  
• 26% Washington, D.C.
• 10% Howard, Ann Arundel, Calvert, Baltimore, Charles Counties, Maryland and Northern Virginia