Like other border states such as Delaware and Kentucky, Maryland was politically and socially tied to both the North and the South. Its urban areas were primarily Northern in character, but the eastern part of the state, around the Tidewater region had an agrarian economy which was supported by slaves. The plantations in the Tidewater area produced many agricultural products including corn, wheat, and tobacco.
The land area that eventually became Maryland was known to European explorers in the sixteenth century, but it didn't interest colonists until the English settled there in the seventeenth century. In 1632, Charles I of England granted George Calvert, the first Lord of Baltimore, land between the 40th parallel line and Virginia. Calvert, who was Catholic, wanted to create a safe haven for Catholics who were persecuted in England. As in Virginia, African slaves accompanied the English settlers to Maryland. Maryland remained a proprietary colony until the American Revolution.
Baltimore grew rapidly in the eighteenth century and became an important port. During the 1760s, Pennsylvanians and Marylanders clashed over the issue of their border. To settle this dispute, Charles Mason and Jeremiah Dixon surveyed the land to determine the border. Their survey resulted in the Mason-Dixon line, which later became known as the line dividing the slave and free states.
Marylanders were strong supporters of American independence. In 1774, an independent convention was held in Annapolis and representatives from each state attended. After the Revolutionary War, the Continental Congress assembled again in Annapolis to ratify the Treaty of Paris (the treaty granting independence to the U.S.) and to accept George Washington's resignation from the Continental Army.
In the early nineteenth century, Maryland grew economically, as ships built in Maryland increasingly conducted international commerce, supplying European nations embroiled in the Napoleonic Wars with supplies. After the British were defeated in the War of 1812, Maryland expanded economically with railroads, public roads, and canals. Agriculture, however, continued to be an important element of the state's economy, with African slaves providing the labor on plantations.
There were, according to the U.S. Census of 1860 (the last census before the Civil War), 87,189 slaves, 83,942 free colored persons, and 515,918 whites in Maryland. When the Civil War began, troops from the North passed through Maryland to protect Washington, D.C., from Southern forces. However, on April 19, 1861, a mob from Baltimore attacked these troops, and Northern troops subsequently occupied Maryland during the remainder of the Civil War in order to ensure its allegiance to the Union. In fact, however, Marylanders fought on both sides of the War, and the battles of Monocacy, Sharpsburg (or Antietam), and South Mountain were fought in Maryland. In the post-Civil War years, Maryland grew rapidly and experienced significant urban and industrial expansion. As a result, the state became increasingly Northern in character.