Upper Marlboro

The incorporated Town of Upper Marlboro is 0.4 square miles, less than one mile across and half a mile wide. 4.65% (0.04 square miles) of that is water. Once a port town, the Town is on the Western Branch of the Patuxent River. The main stem of the Patuxent River, not far from the Town,  forms the eastern boarder of Prince George’s County.

The Town is among the oldest of the surviving southern Maryland towns with a history dating back to colonial times. The area was settled around 1695 and named after the first Duke of Marlborough — an ancestor of Winston Churchill. It was established as a port town for tobacco shipments  in 1706, when the western branch of the Patuxent River was still navigable for tobacco vessels.  It has been the county seat of Prince George’s County since 1721.

The town is the birthplace of John Carroll, the first Catholic Archbishop in America and founder of Georgetown University, and of his brother Daniel, a signer of the U.S. Constitution. Throughout its history, Upper Marlboro has been the home or place of work of prominent national, state, and local officals.

When people make reference to Upper Marlboro or Marlboro, may not be referring to the “Town”. There are two ZIP codes that the United States Post Office has labeled “Upper Marlboro” (20772 and 20774), as well as three post office boxes (20773, 20775 and 20792). These Zip codes constitute Greater Upper Marlboro, a geographical area that is about one-fifth of the total area of Prince George’s County!