during the Civil War, Union armies were supplied by steamboats that used the Potomac and James rivers to bypass Confederate forces and avoid poor roads, and City Point (pictured above) became a major port
Source: The Photographic History of the Civil War, Military Commerce (p.133)
In 1784, Virginia gave James Rumsey a 10-year license to operate steamboats on the Potomac River, in part because he was endorsed by George Washington. Rumsey successfully tested a steamboat in 1787 at Shepherdstown (now in West Virginia).
That same year, Rumsey's rival John Fitch tested a steamboat on the Delaware River. James Madison supported Fitch's efforts and Virginia issued him a license, but he became embroiled in patent disputes and did not initiate steamboat operations. Robert Fulton later commercialized the technology and is often credited with being the inventor, but a monument near Harpers Ferry commemorates Rumsey's earlier efforts.1
In 1813, regular steamboat service started on the Potomac River. Different boats ran from Washington DC to Marlboro Point/Aquia Creek (near Fredericksburg) and Richmond. Service between Richmond and Baltimore started in 1815, and between Richmond and Norfolk in 1816. The Old Bay Line started in 1840, and offered overnight service between Baltimore and Norfolk, Point Comfort, and Richmond.
Several Old Bay Line steamboats operating on the Potomac River were seized by the Union forces at the start of the Civil War. (After World War II, one of its ships that has steamed between Baltimore-Norfolk was purchased, transferred to the Mediterranean, renamed the SS Exodus, and gainedfame after the British blocked it from landing Jewish refugees in Palestine.) When the Old Bay Line ceased operations on the Chesapeake Bay in 1962, no other company in the US was still offering overnight steamship passenger service.2
During the first year of the Civil War, Confederates blockaded the Potomac River by placing cannon at several bluffs on the Prince William County shoreline. In contrast to the War of 1812, when British ships had to wait five days before getting a favorable wind in order to sail past the American battery at Belvoir, Union ships could move independently from weather conditions. The US Navy never mounted an effective attack on the Potomac River batteries. It regained control of the Potomac River only after Confederates withdrew in March, 1862 when the Peninsula Campaign threatened Richmond.
General McClellan changed his base during the Peninsula Campaign, and steamships that had carried supplies to White House on the Pamunkey River switched to Berkeley Plantation (Harrison's Landing)
Source: The Photographic History of the Civil War, Loading the Transports (p.272)
Starting in March 1862, the Union Navy gained control of nearly all Tidewater Virginia rivers and Chesapeake Bay. The Elizabeth River was the last to come under Union control, except for the James River upstream of Fort Darling on Drewry's Bluff. Confederates controlled that stretch and blocked Union warships from steaming up the James River to Richmond, until Fort Darling was abandoned after the fall of Petersburg in April 1865.
When the Peninsula Campaign led to a concentration of forces at Fort Moroe in March 1862, the CSS Virginia ironclad sailed out of the Elizabeth River and easily defeated several wooden warships in Hampton Roads. The timely arrival of the USS Monitor led to the first battle of ironclad, steam-powered warships. While neither ironclad could destroy the other, the Union Navy was able to keep the CSS Virginia bottled up in the Elizabeth River, allowing steamboats to bring massive amounts of supplies for the Peninsula Campaign up the York River to White House Landing.
the CSS Richmond was a Confederate ironclad constructed initially at the Norfolk Navy Yard, completed in Richmond after the Confederates abandoned Hampton Roads, and trapped upstream of Drewry's Bluff for the rest of the Civil War
Source: US Navy - Naval Historical Center, CSS Richmond (1862-1865)
President Lincoln is credited with organizing the Union Army attack on Norfolk, which led to the Confederates destroying the CSS Virginia. That ship is the most famous Confederate ironclad, but others were constructed at the Norfolk Navy Yard and Richmond. They remained in the James River, upstream of Drewry's Bluff, throughout the war. Federal barricades in the river prevented those other Confederate ironclads from threatening Union shipping until the war ended, though the James River Squadron made one major-but-unsuccessfully attempt to break out and go on the offensive in January, 1865.
the James River Squadron of the Confederate Navy was unable to get past Federal barricades and ships after March, 1862, so the Union Navy could use Virginia waterways with impunity for most of the Civil War
Source: Harper's Weekly, "The Rebel Iron-Clad Fleet Forcing the Obstructions in James River" 23 January 1865
starting in the 1820's, tourists traveled to hotels on Old Point Comfort via steamship
Source: Internet Archive, A history of Old Point Comfort and Fortress Monroe, Va., from 1608 to January 1st, 1881 (1881)
Union steamboats transported troops via the Chesapeake Bay throughout the Civil War
Source: Frank Leslie's Illustrated History of the Civil War, The New Jersey Troops Crossing the Chesapeake Bay, in Sixteen Propellers, on Their Way to Washington, May 4, 1861 (p.182)
Union General McClelland planned the 1862 Peninsula Campaign to take advantage of steamboats, and assumed the Confederates had no significant naval forces that could interrupt water-based supply lines to White House Landing
Source: Frank Leslie's Illustrated History of the Civil War, White House Landing, Pamunkey River VA The Grand Depot of the Commissariat and Ordnance Department of the Army Before Richmond (p.142)
after General McClellan grew alarmed at agressive attacks by General Lee, the Union forces abandoned White House Landing and changed their supply base to Harrison Landing (Berkeley Plantation) on the James River
Source: Frank Leslie's Illustrated History of the Civil War, Burning of the White House - The Federal Troops By Command of General McClellan Abandoning Their Position at the White House and Breaking Up the Commissariat Depot on the Pamunkey River - Departure of the Union Flotilla For the James River June 26th 1862 (p.192)