Stats and Facts

St. Mary’s County is situated on a peninsula in Southern Maryland with over 500 miles of shoreline on the Patuxent River, Potomac River and Chesapeake Bay. The Naval Air Station, Patuxent River, employing 22,400 military, civilians and defense contractors, is home to the U.S. Naval Air Systems Command (NAVAIR), including the Naval Air Warfare Center Aircraft Division (NAWCAD). With over 200 high-tech aerospace and defense contractors, the county has emerged as a world-class center for maritime aviation research, development, testing, evaluation, and acquisition.

The area combines access to technology with a rich heritage and a myriad of outdoor sports and recreational opportunities. The county’s location allows for easy access to major metropolitan areas while offering residents a high quality of life and affordable lifestyles. St. Mary’s County’s 1,990 businesses employ 28,000 workers; an estimated 50 of these businesses have 100 or more workers. Businesses include DynCorp International, Wyle, BAE Systems, SAIC, L-3, Lockheed Martin, Northrop Grumman, and many others. Non-defense employers include St. Mary’s Hospital, St. Mary’s College of Maryland, Burch Oil, and the Paul Hall Center for Maritime Training and Education.

Climate and Geography

Yearly Precipitation (inches) 46.2
Yearly Snowfall (inches) 14.5
Summer Temperature (ºF) 75.3
Winter Temperature (ºF) 37.6
Duration of Freeze-Free Period (days) 283.6
Land Area (square miles) 372.5
Water Area (square miles) 37.7
Shoreline (miles) 536
Elevation (feet) sea level to 192


St. Mary’s County Households (2010) 38,450
St. Mary’s County Population (2014)  110,382

Population Distribution (2014)

Age Number Percent
Under 5 7,277 6.82
5 – 19 23,239 22.16
20 - 44 36,567 31.42
45 – 64 30,046 28.54
65 and over 13,253 11.04
Total 110,382  

Median age: 36.3 years

(Maryland Department of Commerce)


  • Highest percentage of high-tech employment in the region
  • Growth rate 2nd fastest in state 2000-09
  • Annual growth rate 3rd fastest in state
  • 3rd highest birth rate and 6th lowest death rate in state
  • Youngest population in state
  • Highest concentration of military veterans in state
  • Fastest growing workforce in state
  • 3rd highest median household income growth in state
  • 6th lowest unemployment rate in state
  • 14th highest earned income level in the U.S.
  • Leonardtown is the first (and only!) Arts & Entertainment District in Southern Maryland