Question: What African American astronomer and almanac author was born in Baltimore County, Maryland?

Context articles: Historical Society of Baltimore County
Maryland Route 147
Banneker Circle
Glyndon, Maryland
Loch Raven, Maryland
Baltimore County Sheriff's Office (Maryland)
Maryland Route 45
Baltimore County Executive
Baltimore County Circuit Courthouses
Benjamin Banneker

The Historical Society of Baltimore County (HSBC) was founded in 1959 with the goal of preserving and illustrating the history of Baltimore County for the benefit of present and future generations of Marylanders.
 "The Society accomplishes its mission through the production of presentations, lectures, workshops, entertaining educational publications, historical tours, and exhibits."
 Centrally located in Cockeysville, Maryland, the Society operates out of the Agriculture Building, the former Baltimore County Almshouse, which was built in 1872 and used to house the poor and mentally ill of Baltimore County until 1958.
Maryland Route 147 (MD 147) is a state highway in the U.S. state of Maryland.
 Known as Harford Road, the state highway runs 18.81 mi from U.S. Route 1 (US 1) in Baltimore north to US 1 and US 1 Business in Benson.
 MD 147 is an alternate route to US 1 between Baltimore and Bel Air, the county seat of Harford County.
 The state highway is the main street of several neighborhoods in Northeast Baltimore and the Baltimore County suburbs of Parkville and Carney.
 MD 147 is maintained by the Maryland State Highway Administration in Baltimore and Harford counties and by the Baltimore City Department of Transportation within the city.
 Harford Road was a pair of turnpikes before the Baltimore–Carney portion of the highway was designated one of the original state roads.
 The Baltimore County section of MD 147 was constructed in the early 1910s and widened multiple times in the late 1920s and 1930s.
 The section of the state highway in Harford County was built in the late 1920s.
Banneker Circle is a partial traffic circle in Southwest Washington, D.C..
 The name of the circle commemorates Benjamin Banneker, an African American astronomer and almanac author.
 In 1791, Banneker assisted in the initial survey of the boundaries of the District of Columbia.
 The circle is near the south end of L'Enfant Promenade and the intersection of Interstate 395 and Maine Avenue.
 Benjamin Banneker Park is within the Circle.
Glyndon, Maryland is an unincorporated community in Baltimore County, Maryland, United States.
 Founded in 1871 by Dr. Charles A. Leas, the village is located in the northwest section of Baltimore County and is primarily a residential suburb of metropolitan Baltimore City.
 The village is characterized by the predominance of historic Victorian homes and a strong sense of community among its residents.
 Glyndon is listed on the National Register of Historic Places (1973) and on the Maryland Inventory of Historic Properties (1973); the Glyndon Historic District was also designated as the first historic district in Baltimore County (1981).
 Also listed on the National Register of Historic Places is the Worthington Valley Historic District.
Loch Raven, Maryland 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 Blvd, 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 as 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 still a 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, Maryland zip code.
The Baltimore County Sheriff's Office (BCoSO) is the enforcement arm of the Baltimore County, Maryland court and is headquartered in the Baltimore County Courthouse, in the County Seat of Towson, Maryland.
 The Baltimore County Sheriff's Office is one of the oldest sheriff's offices in existence in the State of Maryland, dating back to 1659, the traditional year of the County's "erection" (founding).
Maryland Route 45 (MD 45) is a state highway in the U.S. state of Maryland.
 Known for most of its length as York Road, the state highway runs 30.06 mi from U.S. Route 1 (US 1) in Baltimore north to the Pennsylvania state line in Maryland Line, where the highway continues as SR 3001.
 MD 45 is the primary highway between Downtown Baltimore and Towson, the county seat of Baltimore County.
 North of Interstate 695, the state highway parallels I-83 and serves the suburban communities of Lutherville, Timonium, Cockeysville, and Hunt Valley.
 MD 45 also connects the northern Baltimore County communities of Hereford and Parkton.
 The state highway is maintained by the Maryland State Highway Administration in Baltimore County and by the Baltimore City Department of Transportation in the city, where the highway also follows Greenmount Avenue.
The Baltimore County Executive is the highest elected official representing the government of Baltimore County, Maryland.
 The post was established with the implementation of the Home Rule Charter for Baltimore County on December 6, 1956.
 Previously the powers of the County Executive were vested with the Board of County Commissioners in Baltimore County, which with the implementation of the Home Rule Charter ceased to exist.
 The County Executive is elected to post every 4 years, coinciding with the elections for the county council and governor of Maryland.
The Baltimore County Courthouses are located in Towson, the older original Baltimore County Courthouse ("Historic Courthouse") of 1854-1856 (and three additions to eventually form an 'H' shape) houses many of the offices of the County government, of both of the executive branch (county executive and their departments/agencies/boards/commissions, etc.) and the legislative branch (County Council), while the County Courts Building ("new" courthouse to the west separated by a plaza) of 1970-1971 is dedicated to the civil, criminal, family and juvenile divisions of the Circuit Court of Maryland for Baltimore County, as well as the Baltimore County Sheriff's Office with its protection of the Courthouse and its judicial personnel and law enforcement functions.
Benjamin Banneker (November 9, 1731October 9, 1806) was a free African American almanac author, surveyor, naturalist, and farmer.
 Born in Baltimore County, Maryland, to a free African American woman and a former slave, Banneker had little formal education and was largely self-taught.
 He is known for being part of a group led by Major Andrew Ellicott that surveyed the borders of the original District of Columbia, the federal capital district of the United States.