Pennsylvania Avenue SE Corridor, is a cultural landscape located in southeast Washington, D.C. The segment of the avenue included in this cultural landscape inventory runs diagonally for 1.3 miles between Second Street SE and Barney Circle. The Pennsylvania Avenue, SE Corridor cultural landscape is comprised of National Park Service reservations 037 – 043, 044A, 047A, 047B and 050 - 054. These reservations include the 16 traffic medians that run down the center of the avenue and 13 surrounding triangle parks.

Pennsylvania Avenue SE Corridor is listed on the National Register as part of the 1997 L’Enfant Plan of Washington, D.C. The National Register lists the period of significance as 1791-1942. The landscape is listed in the following areas of significance: community planning and development; landscape architecture; politics and government; and transportation. Pennsylvania Avenue SE Corridor is also listed as part of the Capitol Hill Historic District, which was added to the National Register in 1976. The period of significance for the historic district is listed as 1791-1901. The areas of significance are listed as: architecture; community planning; military; and local neighborhood history. This CLI maintains that Pennsylvania Avenue SE Corridor is eligible under National Register Criteria A and C, and recommends adding two additional periods of significance: 1862-1962 and 1965-1968. These periods of significance will recognize the role of Pennsylvania Avenue SE Corridor in the development of public transportation in Washington, D.C, and the improvement and beautification of urban recreational areas along the avenue.


Located in the heart of the historic Capitol Hill neighborhood, Pennsylvania Avenue SE Corridor, has served as a local commercial route since the mid-19th century. The avenue was first laid out as part of Pierre L’Enfant’s plan for the city of Washington, in 1791. Despite its proximity to the Capitol building, the surrounding neighborhood remained largely undeveloped until after the Civil War. Pennsylvania Avenue SE was unpaved until the 1870s, though the blocks immediately southeast of the Capitol building were graveled over in 1858. Installation of the city’s first streetcar line in 1862 drove increased commercial investment along the avenue, and citywide improvements to infrastructure led to the eventual paving of the avenue between Capitol Hill and 11th Street SE in the 1870s. Sewers were laid under the street at this time, streetlights installed and trees planted along sidewalks and traffic medians. The triangle parks surrounding the avenue were first delineated and improved with landscaping in the 1880s.

Streetcars ran through the center of Pennsylvania Avenue SE Corridor for 100 years before bus service officially replaced them in 1962. The streetcar line that ran down Pennsylvania Avenue SE Corridor was the first in Washington, DC. as well as the last in operation in the 1960s. Tracks were pulled up, sodded and planted over with turf grass, flowering trees and shrubs in 1965, as part of Phase I of Lady Bird Johnson’s Beautification Project. In the 1970s many of the squares along Pennsylvania Avenue SE Corridor were excavated during construction of the city’s Metrorail. Eastern Market and Potomac Avenue Metro Stations opened below Pennsylvania Avenue, SE Corridor in 1977. Reservations surrounding the Eastern Market Metro Station were transferred to Washington, DC. in the 1970s. In 2001, squares and parks along Pennsylvania Avenue, SE Corridor, were identified as potential sites of future memorials in the National Capital Planning Commission’s Comprehensive Plan for the National Capital.

Historic Maps and Images
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Analysis and Evaluation

The Pennsylvania Avenue SE Corridor Cultural Landscape Inventory finds that Pennsylvania Avenue SE Corridor retains integrity from all three periods of significance: the L’Enfant Plan (1791-1792), the streetcar era (1862-1962) and the Lady Bird Beautification Project (1965-1968). Pennsylvania Avenue SE Corridor has retained many of its landscape characteristics and features and displays many of the seven aspects that determine integrity as defined by the National Register of Historic Places including: location, design, setting, feeling and association.

Contributing landscape characteristics identified for Pennsylvania Avenue SE Corridor are spatial organization, land use, circulation, small-scale features, vegetation, views and vistas and archeology.

Spatial Organization: The current spatial organization of Pennsylvania Avenue, SE Corridor is similar to that envisioned by Pierre Charles L’Enfant during the first period of significance. The primary organizing element from this period is the diagonal axis of the street. The diagonal has been maintained since it was first laid out by Andrew Ellicot and Benjamin Banneker circa 1792. Subsequent modifications to the street have maintained the original diagonal design, though streetcar tracks and modern paving, installed in the 1860s and 1870s, divided two of L’Enfant’s original squares into a series of smaller triangles. Neither L’Enfant nor Ellicott delineated the small triangle parks along Pennsylvania Avenue, though their creation is a result of L’Enfant’s design, and its combination of orthogonal streets with diagonal avenues. Their delineation during the second period of significance is in keeping with the original spatial organization, and the Pennsylvania Avenue SE Corridor landscape retains a high level of integrity to the first and second periods of significance.

Land Use: The Pennsylvania Avenue SE Corridor has a consistent history of land use,  as a mode of transportation, since it was laid out circa 1792. During the first period of significance pedestrians, horsemen and horse drawn carts shared the entire width of the road. During the second period of significance, the city’s first streetcar line ran down the center of the avenue. Even after the streetcar tracks were sodded over, during the third period of significance, the new traffic medians served an important transportation function, by separating oncoming traffic on a busy downtown street. These Pennsylvania Avenue SE medians retain high integrity to their use during the first, second and third periods of significance. The triangle parks along the avenue were first developed and designed as small, green “breathing spaces” during the second period of significance and continue to serve that function. These reservations retain a high degree of integrity of use to the second period of significance.

Circulation: The key historic circulation feature of the Pennsylvania Avenue SE Corridor is the avenue itself. The street has been a functioning thoroughfare since the first period of significance. Small medians were first installed along the avenue during the second period of significance to separate the streetcar from other vehicles. Since the streetcar tracks were sodded over during the third period of significance, circulation along the medians is limited to social trails running between the trees and across the avenue—still the medians retain partial integrity of circulation to the second periods of significance, when medians were first installed, and high degree of integrity to the third period of significance. Squares and triangle parks along the avenues were not developed until the second period of significance, during which time pedestrian circulation was designed for some of these spaces. These circulation patterns were generally maintained during the beatification projects of the 1960s, though some were redesigned in the 1970s during the construction of the Metrorail. As a result, the triangle parks retain partial integrity to the second period of significance.

Vegetation: There is no record of the type of vegetation that existed along the Pennsylvania Avenue SE Corridor during the first period of significance. During the second period of significance rows of trees were planted along the narrow medians separating the streetcar from the street. Some of these trees were maintained when the medians were sodded and replanted with turf and double rows of magnolia trees, during the third period of significance. The original magnolias were replaced with flowering crabapples in the late 1990s, though the overall planting plan from the 1965 was retained, and turf grass continues to serve as the main ground cover for all medians. Many of the triangle parks still contain trees dating to the second period of significance. Thus, the Pennsylvania Avenue SE Corridor cultural landscape retains some integrity of vegetation to the second and third periods of significance. 

Views and Vistas: Pennsylvania Avenue SE Corridor’s unobstructed view of the Capitol building, designed by L’Enfant, was partially obstructed by the Library of Congress building, completed in 1897. Despite the compromised nature of the main vista along the avenue, many of L’Enfant’s designed vistas along the orthogonal streets have been maintained. No significant views or vistas were designed during the other periods of significance and the avenue retains integrity to the original L’Enfant plan.

Small-Scale Features: Nearly all small scale features within the Pennsylvania Avenue SE Corridor post-date the periods of significance except for some curbing installed in the 1870s and early 1900s. The site retains a small degree of integrity of small scale features to the second period of significance.

Archeology: No significant archeological investigations have been conducted within the Pennsylvania Avenue SE Corridor though sections of the street and surrounding parks have been excavated, most recently in the 1970s, for the installation of the Metrorail. Archeological studies in the surrounding areas, including the excavation of Barney Circle and Virginia Avenue, have uncovered original cobblestone streets and artifacts dating to various period of inhabitation, including pre-Columbian. Past use indicates that the Pennsylvania Avenue SE Corridor may contain archeological material related to the history of transportation in Washington, DC. Archeological evidence of early Colonial and Native American settlements may also be present.

Current Photographs
Final Report

The final report is available on the National Park Service website here.

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