Frederick is a city in, and the county seat of, Frederick County, Maryland, United States. It is located at an important crossroads at the intersection of a major north–south Native American trail and east–west routes to the Chesapeake Bay, both at Baltimore and what became Washington, D.C., and across the Appalachian mountains to the Ohio River watershed. Frederick's population was 78,171 people as of the 2020 census, making it the second-largest incorporated city in Maryland behind Baltimore. It is a part of the Washington metropolitan area and the greater Washington–Baltimore combined statistical area.
The Baltimore and Ohio Railroad was the first common carrier railroad and the oldest railroad in the United States. It operated as B&O from 1830 until 1987, when it was merged into the Chessie System; its lines are today controlled by CSX Transportation.
U.S. Route 340 is a spur route of US 40, and runs from Greenville, Virginia, to Frederick, Maryland. In Virginia, it runs north–south, parallel and east of US 11, from US 11 north of Greenville via Waynesboro, Grottoes, Elkton, Luray, Front Royal, and Berryville to the West Virginia state line. A short separate piece crosses northern Loudoun County on its way from West Virginia to Maryland.
The Potomac Heritage Trail, also known as the Potomac Heritage National Scenic Trail or the PHT, is a designated National Scenic Trail corridor spanning parts of the mid-Atlantic region of the United States that will connect various trails and historic sites in Virginia, Maryland, Pennsylvania, and the District of Columbia. The trail network includes 710 miles (1,140 km) of existing and planned sections, tracing the natural, historical, and cultural features of the Potomac River corridor, the upper Ohio River watershed in Pennsylvania and western Maryland, and a portion of the Rappahannock River watershed in Virginia. The trail is managed by the National Park Service and is one of three National Trails that are official NPS units.
The Monocacy River is a free-flowing left tributary to the Potomac River, which empties into the Atlantic Ocean via the Chesapeake Bay. The river is 58.5 miles (94.1 km) long, with a drainage area of about 970 square miles (2,500 km2). It is the largest Maryland tributary to the Potomac.
Catoctin Mountain, along with the geologically associated Bull Run Mountains, forms the easternmost mountain ridge of the Blue Ridge Mountains, which are in turn a part of the Appalachian Mountains range. The ridge runs northeast–southwest for about 50 miles (80 km) departing from South Mountain near Emmitsburg, Maryland, and running south past Leesburg, Virginia, where it disappears into the Piedmont in a series of low-lying hills near New Baltimore, Virginia. The ridge forms the eastern rampart of the Loudoun and Middletown valleys.
White's Ferry, originally Conrad's Ferry, is an inactive cable ferry service that carried cars, bicycles, and pedestrians across the Potomac River between Loudoun County, Virginia and Montgomery County, Maryland, and is the last one of its kind to cross the Potomac. The location offered fishing services and water recreation including canoeing. It transported between 600 and 800 customers daily until its operations were suspended indefinitely in 2020 due to a legal dispute over the land surrounding it.
Adamstown is an unincorporated community and census-designated place (CDP) in Frederick County, Maryland, United States. It is named for Adam Kohlenberg, a station agent and first town merchant who owned much of present-day Adamstown. As of the 2010 census, the Adamstown CDP had a population of 2,372.
Maryland Route 17 is a state highway in the U.S. state of Maryland. The state highway begins at the Virginia state line at the Potomac River in Brunswick, where the highway continues south as Virginia State Route 287. MD 17 runs 29.49 miles (47.46 km) north from the Brunswick Bridge to the Frederick–Washington county line near Wolfsville. The state highway serves as the main north–south highway of the Middletown Valley of western Frederick County. MD 17 connects Brunswick and Wolfsville with Rosemont, Burkittsville, Middletown, and Myersville. The state highway also connects those communities with the valley's main east–west highways, which include U.S. Route 340, US 40 Alternate, Interstate 70 (I-70), and US 40.
Loudoun County, Virginia, was destined to be an area of significant military activity during the American Civil War. Located on Virginia's northern frontier, the Potomac River, Loudoun County became a borderland after Virginia's secession from the Union in early 1861. Loudoun County's numerous Potomac bridges, ferries and fords made it an ideal location for the Union and Confederate armies to cross into and out of Virginia. Likewise, the county's several gaps in the Blue Ridge Mountains that connected the Piedmont to the Shenandoah Valley and Winchester were of considerable strategic importance. The opposing armies would traverse the county several times throughout the war leading to several small battles, most notably the Battle of Ball's Bluff.
Buckeystown is an unincorporated community and census-designated place (CDP) in Frederick County, Maryland, United States. As of the 2010 census the population was 1,019. Buckeystown Historic District and Buckingham House and Industrial School Complex were listed on the National Register of Historic Places in 1982. Carrollton Manor was listed in 1997. Former Congressman Roscoe Bartlett lives on a farm in the town.
The Metropolitan Subdivision is a railroad line owned and operated by CSX Transportation in the District of Columbia and the U.S. state of Maryland. The 53-mile line runs from Washington, D.C., northwest to Weverton, Maryland, along the former Metropolitan Branch of the Baltimore and Ohio Railroad.
U.S. Route 15 (US 15) is a part of the United States Numbered Highway System that runs from Walterboro, South Carolina, north to Painted Post, New York. In Maryland, the highway runs 37.85 miles (60.91 km) from the Virginia state line at the Potomac River in Point of Rocks north to the Pennsylvania state line near Emmitsburg. Known for most of its length as Catoctin Mountain Highway, US 15 is the primary north–south highway of Frederick County. The highway connects the county seat of Frederick with Point of Rocks, Leesburg, Virginia, and Charles Town, West Virginia, to the south and with Thurmont, Emmitsburg, and Gettysburg, Pennsylvania, to the north. US 15 is a four-lane divided highway throughout the state except for the portion between the Point of Rocks Bridge and the highway's junction with US 340 near Jefferson. The highway is a freeway along its concurrency with US 340 and through Frederick, where the highway meets US 40 and Interstate 70 (I-70). US 15 has a business route through Emmitsburg.
Monocacy is a passenger rail station on the MARC Brunswick Line between Washington, D.C. and Frederick, Maryland. This station is one of two stations on the Frederick extension. It is also the only station on the Brunswick Line other than Union Station to have a high-level platform. There is also a low level platform at the north end of the station.
The action at Mount Zion Church was a cavalry skirmish during the American Civil War that took place on July 6, 1864. The skirmish was fought between Union forces under Major William H. Forbes and Confederate forces under Colonel John S. Mosby near Aldie in Loudoun County, Virginia as part of Mosby's Operations in Northern Virginia. After successfully raiding the Union garrison at Point of Rocks, Maryland, Mosby's Rangers routed Forbes's command, which had been sent into Loudoun County to engage and capture the Rangers. The fight resulted in a Confederate victory.
Nolands Ferry I Archeological Site is an archaeological site near the historic Noland's Ferry boat landing at mile 44.58 on the C&O Canal and Tuscarora. The Archeological Site is a prehistoric occupation site located in the Monocacy region of southern Frederick County, Maryland. Diagnostic artifacts at the site indicate that the site was almost continuously inhabited from the Paleo-Indian period to the early 19th century, with the most substantial inhabitation occurring during the Late Woodland period.
The 1st Maryland Infantry Regiment, Potomac Home Brigade was an infantry regiment that served in the Union Army during the American Civil War.
1st Maryland Cavalry Battalion, Potomac Home Brigade, originally organized as the 1st Potomac Home Brigade Cavalry, "Cole's Cavalry" was formed under the guidance of Henry A. Cole. There are also references to it being designated as Cole's 1st Volunteer Maryland Cavalry. The unit, a battalion, originally consisted of four companies, A, B, C & D and was initially enlisted between August 10 and November 27, 1861.
United States
Maryland 
Frederick 
