Deep Run (Patapsco River tributary)

The Elkridge Furnace Complex is a historic iron works located on approximately 16 acres (6.5 ha) at Elkridge, Howard County, Maryland.

Herbert Run is a .413-mile-long (0.665 km) stream that flows through Baltimore County. It is a tributary of the Patapsco River, which flows into the Chesapeake Bay. Herbert Run divides into two tributaries, East Branch Herbert Run and West Branch Herbert Run, to the north. The headwaters of the East Branch are located near the Banneker Community Center in the neighborhood of Catonsville. The headwaters of the West Branch are located near Spring Grove Hospital Center in Catonsville.

First Baptist Church of Elkridge, is a historic African American Church located at 5795 Paradise Ave in Elkridge, Maryland. The building was constructed in 1877.

Elkridge is an unincorporated community and census-designated place (CDP) in Howard County, Maryland, United States. The population was 15,593 at the 2010 census. Founded early in the 18th century, Elkridge is adjacent to two other counties, Anne Arundel and Baltimore.

St. Denis station is a passenger rail station on the MARC Camden Line in the Maryland town of the same name. While the small station is the line's closest station to its terminus at Camden Yards in Baltimore, it has low ridership. St. Denis station contains two platforms and three tracks. The southbound platform, located on the corner of Arlington and Maple Avenues, has a shelter that is made of plexiglas and aluminum. MARC gives this platform as the official address of the station. The northbound platform contains a wooden shelter on an embankment at the end of East Street with the name of the station on the back of it. The station also contains two at-grade wooden pedestrian crossings, one which spans the entire right-of-way from Arlington Avenue to East Street, and the other which only runs from the southbound platform on Maple Avenue to the middle tracks. East of St. Denis, the Camden Line crosses over the MARC Penn Line south of the Halethorpe MARC station. The station itself, is an excellent spot for railfanning due to its proximity to Baltimore and its location at a point that sees Capital Subdivision, Baltimore Terminal Subdivision, and Old Main Line Subdivision freight traffic. A junction leading to the B&O Railroad Museum also exists between here and the terminus at Camden Yards.

The Friendship Annex, also known as FANX or FANEX, is a National Security Agency (NSA) facility complex located in Linthicum, Maryland, near the Baltimore Washington International Airport (BWI). Established in the 1970s, the complex consists of multiple buildings and serves multiple roles as a cyber espionage station, electronic intelligence processing facility, and NSA Broadcast Network television studio. It is also the primary campus of the National Cryptologic School.

Relay, Maryland, or Relay House, Maryland, was formerly an important junction and rail stop on the Baltimore and Ohio Railroad, located 9 miles (14 km) west of Baltimore, Maryland. It was the busiest station on the line except for Baltimore itself. A town grew up around it: a general store, a school, and a volunteer fire company. Although the neighborhood is still inhabited, only the ghost of the town survives. There is no longer town government, a post office, nor are there any stores. The former fire house, at 1710 Arlington Avenue, at one point the town hall, has survived and is available for rental for events. In 2021 Relay is a historic district of Halethorpe, Maryland, near the intersection of today's Viaduct and Railroad Avenues. There is a Relay Elementary School.

The Hockley Forge and Mill are a collection of colonial-era industrial buildings along the Patapsco River near modern Elkridge, Maryland. Located at the river's head of navigation, the site is a flat section of land along the Patapsco River valley with steep embankments on either side. At its 19th-century peak, the site held more than 30 industrial buildings. Initially, the site was the Patapsco crossing of the "Old Indian Road" surveyed by Oliver Cromwell in 1734. In 1760, the forge site was surveyed by Edward Norwood; the forge itself was founded June 14 by Charles Carroll of Carrollton as the "Baltimore Company. Other partners included Charles Carroll of Duddington, Daniel and Walter Dulany, Charles Carroll (barrister) and Benjamin Tasker, Sr. who also operated two other forges. Operated by slaves, the forge produced goods to replace ones imported from England.When the old Baltimore forge burned down in April 1772, slaves were sent to work at the Hockley Forge.In 1781, the state of Maryland seized the company once owned in part by two Dulany cousins who were loyal to the British. Dan Dulany of Baltimore owned a remaining interest in the forge, and wrote the state to reimburse him for the loss in value due to losses sustained by loyalists in the colonial war. He cited that at the time, the forge property contained 100 acres and was operated by 98 slaves valued at 40 pounds each.Forge work depended on a declining supply of coal and wood which idled the plant in 1783. In 1794, Christopher Johnston purchased the property and sold the equipment from the slitting mill to George Elliott for his upstream mill in 1807. The property was auctioned on September 16, 1819, renovated by the Carroll and Oliver families and resold in 1822. A large distillery operation was put into operation by John McKim Jr. which ceased by 1833 when the Thomas Viaduct construction began. The mill continued in operation by George T Worthington until a fire in 1856. In 1868, a major flood damaged the four-story mill. The Levering family acquired the site and sold it in 1876 to the Viaduct Manufacturing Company. A street through the site is now named Levering Avenue. From 1906-1910, a 20-by-30-foot room was rented to Marion B. Davis, who manufactured brass screw threads and socket assemblies for automobiles delivered by horse and carriage. The Viaduct Company produced telegraph equipment onsite until it was abandoned in 1914. Since 1914, most of the remaining buildings have been demolished or destroyed by fire or flood.

The Thomas Viaduct spans the Patapsco River and Patapsco Valley between Relay, Maryland and Elkridge, Maryland, USA. It was commissioned by the Baltimore and Ohio Railroad (B&O); built between July 4, 1833, and July 4, 1835; and named for Philip E. Thomas, the company's first president. Some claim it to be the world's oldest multiple arched stone railroad bridge. However, the Sankey Viaduct on the Liverpool and Manchester Railway was opened in 1830, and finally completed in 1833. At its completion, the Thomas Viaduct was the largest railroad bridge in the United States and the country's first multi-span masonry railroad bridge to be built on a curve. In 1964, it was designated as a National Historic Landmark. In 2010, the bridge was designated as a National Historic Civil Engineering Landmark by the American Society of Civil Engineers. The viaduct is now owned and operated by CSX Transportation and still in use today, making it one of the oldest railroad bridges still in service.

BWI Rail Station (signed as BWI Thurgood Marshall Airport) is an intermodal passenger station in Linthicum, Maryland near Baltimore/Washington International Airport (BWI). It is served by Amtrak Northeast Corridor intercity trains, MARC Penn Line regional rail trains, and several local bus lines. The station is located just over a mile from the airport's terminal. It was the first intercity rail station in the United States built to service an airport. A free shuttle bus runs between the station and the airport terminal at all hours.Although Penn Station is the Baltimore area's main intercity station, BWI Airport is a major station in its own right. It is Amtrak's sixth-busiest station in the Mid-Atlantic region (behind New York Penn, Washington, Philadelphia, Baltimore Penn, and Albany-Rensselaer), the third-busiest in the Baltimore-Washington corridor, and the 12th busiest nationwide.

The National Electronics Museum, located in Linthicum, Maryland, displays the history of the United States defense electronics. The museum houses exhibits containing assortments of telegraphs, radios, radars and satellites. Located near the Baltimore/Washington International Airport and rail station, the museum displays hands-on electronics. The library serves as a research center open to the public. In addition, an amateur radio station is broadcast live from the museum each week. K3NEM/W3GR includes both antique and updated communication equipment.

Also called the "Day of Playful Invention", Robot fest "is an annual event for anyone interested in the creative use of technology" to promote science, technology, engineering and mathematics (STEM). It takes place at the National Electronics Museum in Linthicum, Maryland and entry is donation based.This year's Robot Fest will occur in April 2021 and include exhibitors such as The Art Institute of Washington, MakerBot Industries and Lego. 2020 saw no event.