Moore House - scene of surrender negotiations at Yorktown, 1781
The Revolutionary War started in Massachusettes. Virginia can claim a leading role in political agitation leading to the war, but little fighting occurred in Virginia for the first 5 years of the conflict.
Massachusetts caught the attention of the British years before the the gunshots started at Lexington and Concord, with the "massacre" in Boston in 1770 and the "tea party" in 1773. The port of Boston was closed to trade, stimulating two Virginia communities still in existence today to name themselves Boston in solidarity. (To distinguish itself from the Culpeper County community, the one in Halifax switched its name to "South Boston.")
In 1775, the Virginia politicians in the House of Burgesses forced Lord Dunmore to act. First he seized the gunpowder stored at the "magazine" in Williamsburg, but that triggered a group of agitators and citizens to march on the town from as far away as Prince William County. Peace was restored briefly when Dunmore agreed to pay for the powder.
When it became clear that this dispute would not be resolved by standard political compromises between the royal governor and the elected House of Burgesses, Dunmore fled his Royal Palace in Williamsburg and moved onto the HMS Fowey. From that safe refuge, he requested troops and ships to help him recapture Virginia in late 1775.
Dunmore managed to capture Norfolk at the very start of 1776, but his requested reinforcements were sent to Boston instead. After the Virginia rebels set fire to loyalist homes in Norfolk, Dunmore finished the job of burning the town and withdrew. In August 1776, his base of operations at Gwynn's Island in Mathews County was attacked. Dunmore's troops were weakened severely by sickness, so he abandoned the "colony" and never returned.
The British knew Virginia was exposed to attack from the sea, and that Virginia had no navy capable of defeating a British warship. However, the focus of the war was in the northern "colonies" until 1780. By that time, General Clinton had abandoned Boston, seized New York, and captured and then abandoned Philadelphia, the home of the rebellious Congress. Norfolk had been destroyed, and the only remaining large population center in the colonies was Charleston, South Carolina. Washington had surrounded New York with the American army, but was unable to gather enough men and supplies to attack the British fortifications.
To break the stalemate, Clinton successfully attacked and seized Charleston in 1780. By opening up a new front in the southern colonies, Clinton hoped to stimulate loyalists and convince the colonists to end the rebellion - or at least to reduce the flow of resources that maintained Washington's army.
Clinton chose not to attack the George Washington's army outside of New York, but instead to wait until the Americans abandoned hope. To demonstrate the futility of continuiing the rebellion and to disrupt supplies and reinforcements for Washington's army, Clinton attacked the stronghold at Charleston.
The British captured 5,000 American soldiers at Charleston, including the Virginia Line (most of the Virginians serving in the Continental Army), before Clinton sailed back to New York and left General Cornwallis to continue the campaign. The defeat of the American army in South Carolina left the southern colonies undefended. George Washington dispatched Nathaniel Greene with orders to assemble a new army and challenge Cornwallis.
After Clinton captured Charleston, Cornwallis marched through South Carolina and North Carolina in an attempt to to kill American soldiers, to destroy more rebel supplies, and to stimulate loyalists to seize control of southern colonies. The British and Americans fought several engagements in the Piedmont, and in most cases the British troops ended up controlling the battlefield at the end of the day. However, at the end of each battle Cornwallis had fewer soldiers and fewer supplies. He turned to the coast and resupplied at Wilmington, North Carolina, then aimed for Virginia in order to disrupt colonial supplies and to punish the Virginia supporters of the rebel cause.
Cornwallis was not the first to attack Virginia since Dunmore sailed away from Gwynn's Island. Several naval raids had seized tobacco and tobacco ships, destroyed warehouses, and frightened the politicians in the General Assembly, and Benedict Arnold succeeded in capturing Richmond in 1780. However, the 7,000 troops under Cornwallis were the largest army ever to invade Virginia - and, except for 1861-65, the last army to do so.
Cornwallis marched to Petersburg first, then ranged throughout central Virginia. Colonel Tarleton led a cavalry raid on Charlottesville, in hopes of capturing the leaders of the General Assembly. Thanks to Jack Jouett, who raced from Louisa County to Charlottesville in time to warn the politicians "the British are coming" in the Virginia version of Paul Revere's ride, only a few members of the rebel legislature were captured. Cornwallis destroyed military supplies stocklpiled along the James River, then planned to go into winter quarters.
He chose a location on the Coastal Plain with a deep harbor, where the British Navy in New York could easily provide new supplies and troops if necessary. After marching to Yorktown, Cornwallis received assurances that he would receive new troops and supplies. However, the French Fleet sailed up from the West Indies to block those reinforcements in the "Battle of the Capes," while George Washington and Count Rochambeau marched the American and French armies from New York to Virginia.
Even after discovering that the British fleet would not perform as promised, Cornwallis did not view Yorktown as a hopeless trap. He had plenty of boats,and control of the river. His escape plan was to transfer the British army across the York River from the Yorktown fortifications to Gloucester County, where Tarleton maintained a fortified base at the tip of the peninsula. Cornwallis could not control the weather, however. After moving 15% of his troops to Gloucester one night, a storm heavily damaged the British boats. Cornwallis chose to abandon the campaign and surrender, rather than to fight a futile battle and create greater casualties.