The Continental Congress met in the Old Senate Chamber from November 26, 1783, to August 13, 1784. During that time, General George Washington came before the Congress to resign his commission as Commander-in-Chief of the Continental Army and the Treaty of Paris was ratified, marking the official end of the Revolutionary War.

The interior of the original section of the State House is constructed of wood and plaster. The newer colonial revival section, which was designed by Francis Baldwin and Josiah Pennington and added between 1902 and 1906, has matched veined Italian marble walls and columns. A broad black line across the columned lobby marks the line between the two sections. The Maryland State House was designated a National Historic Landmark by the Department of the Interior in July 1968.