Long Green Valley Historic District

Hydes is an unincorporated community in Baltimore County, Maryland, United States. It is located in the Long Green Valley. The USPS has assigned Hydes the postal code 21082. Saint John the Evangelist church is located in Hydes and is the oldest Roman Catholic Church in Baltimore County. Until 1958, this community was served by the Maryland and Pennsylvania Railroad at milepost 16.8. It is also home to several wineries, including Boordy and Dejon Vineyards. Hydes is named for Samuel N. Hyde, an agronomist who developed a strain known as "Egyptian" sweet corn, canned by the F.B. Jenkins canning operation of Hydes.

Glen Arm is an unincorporated community in Baltimore County, Maryland, United States. Glen Arm lies along what is now Glen Arm Road, which was once part of Old Harford Road, one of the early routes used for conveying agricultural products from parts of Harford and Baltimore Counties and southern Pennsylvania to the port of Baltimore. Glen Arm was also served until 1958 by the Maryland and Pennsylvania Railroad (the "Ma & Pa"). In 1921, at the railroad's crossing of Glen Arm Road, what generally is recognized as the nation's first train-actuated railroad crossing signal was installed by the railroad's Superintendent of Signals Charles Adler, Jr. Adler later designed early traffic-actuated traffic lights for the City of Baltimore, and also invented the system of flashing warning lights used on aircraft.

Prospect Hill is a historic home located at Long Green, Baltimore County, Maryland, United States. It was designed by architect William Thornton and built between 1796 and 1798. It is a 2+1⁄2-story Federal style brick house.Prospect Hill was listed on the National Register of Historic Places in 1973.

Baldwin is an unincorporated community in Baltimore County, Maryland, United States. The USPS has assigned Baldwin the ZIP Code 21013. Until 1958, this community was served by the Maryland and Pennsylvania Railroad at milepost 18.4. Hidden Valley Farm was listed on the National Register of Historic Places in 1983.

Long Green is an unincorporated community in Baltimore County, Maryland, United States. Until 1958, the community was served by the Maryland and Pennsylvania Railroad at milepost 15.8. Prospect Hill was listed on the National Register of Historic Places in 1973.Long Green was once home to an Amish community. The Amish community in Long Green was founded in 1833 and lasted for 120 years, before disappearing in the 1950s. The community was founded by Lancaster County Amish, but few settlers moved to the area because Maryland was a slave state at the time. Few Amish people crossed the Mason–Dixon line, due to the Amish opposition to slavery. An Amish meetinghouse was constructed in 1899, but the community never grew large. The community dwindled in size over time, with the last Amish person dying in 1953. One of the oldest buildings in Long Green is the Wilson United Methodist Church, built in 1892 in the Gothic Revival style. A previous Methodist meeting house was built in 1839 on land donated by George Wilson, for whom the present church is named. In 1787, noted Methodist leader Francis Asbury preached in the Long Green farmhouse of Wilson's great-uncle. The church's cemetery dates back to the 1850s.

Ravenshurst, or Ravenhurst, was a historic home located at Glen Arm, Baltimore County, Maryland, United States. It was a 2+1⁄2-story Carpenter Gothic-style board-and batten house built about 1854–1857. It was an addition to an earlier stone building thought to have been built about 1800. The home burned on October 31, 1985. Ravenshurst was listed on the National Register of Historic Places in 1978.

Fork is an unincorporated community in Baltimore County, Maryland, United States.

Hidden Valley Farm is a historic home and farm complex located at Baldwin, Harford County, Maryland, United States. It consists of a mid-19th century vernacular Greek Revival brick farmhouse with several auxiliary structures. The house is a three-story, rectangular brick dwelling with a gable roof, with a two-story wing. The house features square-columned one-story porches across the façade and both sides of the wing. Also on the property are a mid-19th century barn, summer kitchen, and smokehouse, and later wood shed and garage.Hidden Valley Farm was listed on the National Register of Historic Places in 1983.

The Perry Hall Mansion is a historic structure located in the area to which it gave its name, Perry Hall, Baltimore County, Maryland, United States. Erected on a hill above the Gunpowder River Valley, the mansion is an excellent example of late colonial and early 19th-century life in eastern Baltimore County.

Germantown is an unincorporated community located in Baltimore County, Maryland, United States. It is part of Perry Hall, and also known as North Perry Hall. Originally, Germantown was centered at the intersection of U.S. Highway 1, also known as Belair Road, and Forge Road. Forge Road branched to the east of Belair Road from Germantown, Baltimore County, Maryland.

Loch Raven is a neighborhood extending from northeast Baltimore City to the eastern part of Baltimore County, Maryland. The major road in the neighborhood is Loch Raven Boulevard, which stretches all the way from the I-695 beltway in Baltimore County to 25th Street in Baltimore City. It is located in the Baltimore Metro Area, and is considered one of the longest roads in the area with many different aspects of Baltimore that can be seen by riding through the area. This region is a diverse, but predominantly African American part of the city and county, and is also the area that consists of a large amount of Morgan State University students. The zip codes assigned to this area are 21218, 21239, 21286, 21284, and 21234, which is also a Parkville zip code.

Perry Hall is an unincorporated community and census-designated place in Baltimore County, Maryland, United States. The population was 28,474 at the 2010 census. It is a suburb of Baltimore.