Monitor and Merrimack, two American warships that fought the first engagement between ironclad ships. When, at the beginning of the Civil War, the Union forces abandoned the Norfolk Navy Yard at Portsmouth, Va., they scuttled the powerful steam frigate Merrimack. She was subsequently raised by the Confederates, converted into an ironclad, and renamed the Virginia. On Mar. 8, 1862, the Virginia, commanded by Capt. Franklin Buchanan, sallied forth into Hampton Roads against the wooden ships of the Union blockading squadron. She rammed and sank the Cumberland, destroyed the Congress after running her aground, and scattered the remaining ships, all the while sustaining practically no damage to herself.

The next day, however, the Virginia, now under command of Lt. Catesby Jones, was challenged by the strange-looking Union ironclad Monitor (see monitor), built by John Ericsson and commanded by Lt. John L. Worden. The Monitor had just reached Hampton Roads after a precarious voyage from New York City. The ships engaged in a four-hour close-range duel, which resulted in a draw. This combat between two ironclad warships marked a revolution in naval warfare.

In April the Virginia, under Capt. Josiah Tattnall, again challenged the Monitor, but the Union ship declined combat. When General McClellan's advance in the Peninsular campaign forced the Confederates to abandon Norfolk, Tattnall, unable to lighten the Virginia sufficiently for passage up the James River, destroyed her (May, 1862). The Monitor foundered and sank in heavy seas off Cape Hatteras in Dec., 1862.

In 1973 scientists discovered the intact wreck of the Monitor, and the site was subsequently protected by the Monitor National Marine Sanctuary. The steam engine and turret of the Monitor were recovered in 2002 for display with other artifacts at the Mariner's Museum, Newport News, Va.

A Week on the Concord and Merrimack Rivers is a book by Henry David Thoreau, first published in 1849. The book is ostensibly the narrative of a boat trip from Concord, Massachusetts to Concord, New Hampshire and back Thoreau had taken with his brother John in 1839. As John had died in 1842, Thoreau wrote the book as a tribute to his memory.

Its first draft was completed while Thoreau lived at Walden Pond. Upon completing the book, Thoreau was unable to find a publisher willing to publish it, and so had it published at his own expense. The book failed to sell, and Thoreau was left with several hundred extra copies, and put into debt. A slightly revised version of the book, based on corrections Thoreau had made himself, was published in 1868, six years after his death.