Completed in 1850, the canal connected Georgetown to Cumberland in Western Maryland by bypassing non-navigable portions of the Potomac River.

Today, Riley's Lock is part of Chesapeake and Ohio Canal National Historical Park.

The lock and surrounding area are known as excellent places for bird watching, and the 40-acre (16 ha) Dierssen Waterfowl Sanctuary is about two miles (3.2 km) away.

[6] Portions of the canal (close to Georgetown) began operating in the early 1830s, and construction ended in 1850 without reaching the intended Ohio River termination.

By 1859, about 83 canal boats per week were transporting coal, grain, flour, and farm products to Washington and Georgetown.

Starting in Baltimore and adding line westward, the B&O Railroad eventually reached the Ohio River and beyond, while the C&O Canal never went beyond Cumberland in Western Maryland.

[10] In 1889, another flood produced an estimated $1 million (equivalent to $33,911,111 in 2023) in damages and caused the company to enter bankruptcy.

[15] The flood damage, combined with continued competition from railroads and trucks, caused the shutdown to be permanent.

[27] An 1865 map of Montgomery County, Maryland, confirms Wood as the lock keeper by showing "Chas.

[28][29] At the beginning of the American Civil War, Union Army leadership realized that the Potomac River area near Locks 23 and 24 was a possible crossing point for a Confederate invasion that could include Washington.

[30] About halfway between Lock 24 and Darnestown, Major General Nathaniel P. Banks kept his headquarters at the Samuel Thomas Macgruder farm where the Potomac River could be observed from high ground.

[31] On June 27, 1863, 5,000 cavalry troops under the command of Confederate General Jeb Stuart crossed the Potomac River near Lock 24.

From there, they advanced to Rockville, Maryland, before rejoining General Robert E. Lee's Army of Northern Virginia in the Battle of Gettysburg.

[36][37] At the age of 69, John Riley died suddenly at his home on April 11, 1931, and was buried at the Darnestown Presbyterian Church cemetery.

[10] A Riley's Lockhouse History Program is run by local Girl Scouts through a special permit from the park.

[44] The Maryland Ornithological Society lists the lock as one of the top birdwatching places in Montgomery County, with over 200 species sited.

[46] An outdoor education camp and the DC National Rowing Club are located nearby on Rileys Lock Road.