Mason and Dixon West Line Milestone Markers 76 and 77

Marsh Creek is a 26.6-mile-long (42.8 km) tributary of the Monocacy River in south-central Pennsylvania and north-central Maryland in the United States.Marsh Creek and Rock Creek join below Gettysburg and the Gettysburg Battlefield to form the Monocacy River. The height of land between Marsh and Rock creeks is the site of the Battle of Gettysburg.

Harney (Monocacyville as late as 1892) is an unincorporated community in Carroll County, Maryland, United States. Harney is also the home of the 'World's Best Carnival'. It has been the home of the Harney Volunteer Fire Company since 1951.

Alloway Creek is a 13.5-mile-long (21.7 km) tributary of the Monocacy River in Pennsylvania and Maryland in the United States. Via the Monocacy River, it is part of the Potomac River watershed.

The Starners Dam Bridge is a steel stringer bridge over Alloway Creek on Baptist Road in Taneytown, Carroll County, Maryland, USA. It is also called Alloway Creek Bridge.

Spangler–Benner Farm is a historic farm and national historic district located at Mount Joy Township in Adams County, Pennsylvania. The district includes nine contributing buildings and two contributing structures. The contributing buildings are the sided log farmhouse (1870), frame bank barn (1864), log summer kitchen (1802), smoke house, spring house, wagon sheds, tools sheds, and machine shops. Contributing structures are a wooden silo and metal windmill, erected in 1900. The farm has been in continuous ownership by the same family since 1802.It was listed on the National Register of Historic Places in 1992.

Horner House and Barn, also known as Alexander Horner House and Locust Grive Farm, is a historic home and barn located at Cumberland Township, Adams County, Pennsylvania. The house was built in 1819, and is a 2+1⁄2-story, five-bay vernacular Federal style dwelling. It has a main block and rear ell, and sits on an uncut fieldstone foundation. The bank barn was built in 1840. The barn has two levels and measures 100.5 by 50 ft (30.6 by 15.2 m). Also on the property is a contributing equipment barn, built in 1916, and an early 19th-century detached summer kitchen.It was listed on the National Register of Historic Places in 2007.

The Bullfrog Road Bridge is a historic bridge between Emmitsburg, Frederick County and Taneytown, Carroll County in Maryland. The bridge crosses the Monocacy River on Bullfrog Road between the two counties. This bridge is a rare steel Parker through truss structure and is 183 feet in length and 16 feet-5 inches in width. It was built in 1908, by the York Bridge Company of York, Pennsylvania.The Bullfrog Road Bridge was listed on the National Register of Historic Places in 1978.

Barlow, Pennsylvania (Horner's Mill during the American Civil War) is a populated place between the Gettysburg Battlefield and the Mason–Dixon line at the intersection of Rock Creek and Pennsylvania Route 134. North of the creek on the road summit is the principal facility of the rural community: the 1939 community hall at the Barlow Volunteer Fire Company fire station. The hall is a Cumberland Township polling place and was used by Mamie & Dwight D. Eisenhower after purchasing their nearby farm (President Eisenhower became an honorary company member in 1955). Horner's Mill was the site of an 1861 Union Civil War encampment, and the covered bridge was used by the II Corps (Union Army) and General George G. Meade en route to the 1863 Battle of Gettysburg. Barlow is located near the U.S. Route 15 interchange to the north and has 3 Taneytown Rd intersections with the Barlow-Greenmount, Barlow, and Barlow-Two Taverns roads. South of the community is a site listed on the National Register of Historic Places (Spangler-Benner Farm) near the Mount Joy Lutheran Church and cemetery. The neighboring communities of Barlow are Greenmount 2.9 mi to the west, Round Top 3.3 mi to the north, Two Taverns 5.1 mi to the east, Harney MD 3.1 mi to the south, and Fairplay 3.2 miles to the southwest.

Cumberland Township is a township in Adams County, Pennsylvania, United States. The population was 7,033 at the 2020 census. In 1863, the American Civil War Battle of Gettysburg took place mainly in Cumberland Township, which surrounds the borough of Gettysburg on three sides.

White Run is a Pennsylvania stream which flows along the Gettysburg National Military Park (East Cavalry Field) and is an eponym of the Rock Creek-White Run hospital complex for field hospitals of the Battle of Gettysburg. The run's mouth is at Rock Creek near the Trostle Farm along the Sachs Road, site of a hospital east of Round Top, Pennsylvania.

Mount Joy Township is a township in Adams County, Pennsylvania, United States. The population was 3,670 at the 2010 census.

Keefer–Brubaker Farm, also known as the Oscar Fogle Farm, is a historic home and farm complex located at Taneytown, Carroll County, Maryland. It consists of a two-story six-by-two-bay log-and-frame house which is partially encased in brick and rests on a rubble stone foundation Also on the property is a frame summer kitchen, a combination smokehouse/dry house, a frame springhouse, a shop building, a bank barn, a dairy, a hog pen, a tool shed, poultry house, and several more recent buildings. It is a representative example of a family farm complex which spans the period from the late 18th century to the mid 20th century.It was listed on the National Register of Historic Places in 2006.