Hampton Roads , an arm of Chesapeake bay, lying between Hampton and Norfolk, Va., forming the estuary of James river. It has a depth of from five to seven fathoms. The channel is commanded by Fortress Monroe, situated on a point of land on the N. shore near the entrance. - A naval action took place here, March 8, 1862, between the confederate ironclad Virginia and the Union frigates Cumberland, Congress, and Minnesota; and another on the 9th between the Virginia and the turret ship Monitor. In April, 1861, the steam frigate Merrimack, lying at Norfolk, was seized by the confederates, set on fire, and then scuttled and sunk. She was subsequently raised, her hull plated with railroad-iron bars, and named the Virginia. Early in March, 1862, there were lying in Hampton roads the United States frigates Cumberland and Congress, the ship St. Lawrence, and the steam frigates Minnesota and Roanoke, the last named being partially disabled by the breaking of her shaft. On the morning of the 8th the Virginia, attended by two small steamers, came down from Norfolk, passed the Congress, receiving a harmless broadside, which was effectively returned, and steered directly for the Cumberland, which she struck with her iron-plated bow, making a large hole, and then opened fire from her battery.

The Cumberland sank in 45 minutes after being struck. The Congress endeavored to escape into shoal water, where the Virginia could not follow, but ran aground, while the Virginia took up a position close under her stern, and poured in a heavy fire, by which the frigate was soon disabled and set on fire. In eight hours the flames reached the magazine, and the vessel was blown up. The St. Lawrence and Roanoke had meanwhile got off and gone down the bay. The Minnesota lay fast aground, and was attacked by the three confederate vessels; but the draft of the Virginia would not permit her to come within a mile, and only one shot from her struck the Minnesota. As night came on, the confederate vessels withdrew. Besides the two frigates, the Union loss was 286; of whom the Cumberland lost 121 killed or drowned, the Congress 100 killed, 26 wounded, and 20 prisoners, and the Minnesota 3 killed and 16 wounded. On the Virginia there were 2 killed and 8 wounded; on the other confederate steamers, 4 killed and several wounded. Early the next morning the Virginia again approached the Minnesota, which was still fast aground.

But in the mean while the Union ironclad Monitor, the first turreted vessel ever brought into action, had arrived from New York, and interposed between the Virginia and the Minnesota. The vessels opened fire, but without giving or receiving damage, the armor of each affording perfect protection. The Virginia now again assailed the Minnesota, and received a full broadside at almost point-blank range, which did no harm. The Monitor kept steaming around the Virginia, searching for a vulnerable point; but her 168-Ib. shot glanced off harmlessly. The Virginia then ran down the bay, as if in retreat, followed by the Monitor, but turned suddenly, and attempted to run down her antagonist, which was hardly one fifth her size. But a blow like that which had pierced the Cumberland made no impression upon the Monitor; and the prow of the Virginia having been slightly damaged, she gave up the battle and steamed toward Norfolk. In this action no one appears to have been injured on the Virginia. Lieut, (after Commodore) Worden, the commander of the Monitor, was badly hurt by particles of cement thrown into his eyes by the concussion of shots which struck the turret, and two sailors were partially stunned by the same concussion. The Monitor remained unharmed.

This action is notable as the first in which iron-clad vessels took part.