French engineers in 1781 mapped the location of Great Bridge, south of Norfolk
Source: Library of Congress, Plan des environs de Williamsburg, York, Hampton, et Portsmouth (1781)
At the time of the American Revolution, Great Bridge was the only place where people could cross the Southern Branh of the Elizabeth River on foot. Captain Johann Ewald, who commanded Hessian troops in the area in 1781, described its significance to control of the region:1
the roads connecting Norfolk with Suffolk and North Carolina passed through Great Bridge
Source: Library of Congress, A Plan of the entrance of Chesapeak Bay, with James and York rivers (by William Faden, 1781)
In December 1775, Lord Dunmore had fled Williamsburg and had occupied Norfolk. To protect the town from Virginia and North Carolina militia and the maintain a reliable supply route from the south, the British built Fort Murray on the northern end of the causeway at Great Bridge and removed planks from the bridge.
About 1,000 rebel soldiers, including the Second Virginia Regiment led by Gen. William Woodford, marched to the south end of the causeway in early December 1775. The British planned to overwhelm them by first launching a diversionary attack nearby, then charging across the bridge.
The diversionary attack was dropped, and on the morning of December 9 the planks were replaced. Captain Charles Fordyce then led a bold charge over the bridge and down the causeway to attack the rebels. Woodford's men waited behind their fortifications until the British soldiers were within 50 yards, then began firing. Within 30 minutes half of the unprotected attackers, including Captain Fordyce in the front, were killed and the British retreated. They spiked their cannon outside of Fort Murray and retreated to Norfolk.
The first significant battle in Virginia between the rebels and the British army ended up as an American victory. The loss of Great Bridge made Dunmore consider Norfolk to be indefensible, and he moved his troops and Loyalist friends onto ships in the Elizabeth River. The ship cannons were used on January 1 to destroy Norfolk, making it useless for the Virginians.2
Lord Dunmore had Fort Murray constructed at Great Bridge in 1775, to control access to Norfolk
Source: Library of Congress, Part of the Province of Virginia (1791)
The Virginians also considered the town to be indefensible, so they completed the destruction by burning structures that survived the cannonnade and abandoned the area. Portsmouth rather than Norfolk became the site for future British occupations in 1779-81.
When Benedict Arnold occupied Portsmouth in 1781, he wanted to control access to the cattle, crops, and other resources in Princess Anne County. He sent Col. John Simcoe and the Queen's Rangers back to Great Bridge, after learning that some of his foragers had been attacked there. The British constructed a massive star fort to control the passage across the South Branch of the Elizabeth River, completing it within three days. For labor, they used 300 formerly enslaved people who had fled from Virginia masters to freedom within the British lines. About 100 men from the 80th Regiment occupied the fort after it was built.3
During construction, Virginia militia fired at the workers and the guards. The British made a dummy, dressed it in a uniform, and posted it as a "sentinel" guarding the approach to the incomplete fort. The rebels fired on the dummy, but the next day it was shown to a Virginia officer who came under a flag of truce. After a discussion about the waste of life from killing sentinels when no attack was planned, the militia stopped that harassment.
Col. Simcoe described the fort's strengths and weaknesses after the war:4
Col. John Simcoe returned to fortify Great Bridge in 1781 when Benedict Arnold occupied Portsmouth
Source: Library of Congress, Plan of the post at Great Bridge, on the south branch of the Elizabeth River, Virginia, establish'd the 5th February 1781 (by James Stratton, 1788)