Georgetown in Northwest Washington in Washington, District of Columbia — The American Northeast (Mid-Atlantic)

Quality Hill - The John Thomson Mason House

3425 Prospect Street Northwest

— Georgetown Historic District —

Quality Hill - The John Thomson Mason House Marker image. Click for full size.

Photographed by J. Makali Bruton, March 23, 2025

1. Quality Hill - The John Thomson Mason House Marker

Inscription. This property has been
placed on the
National Register
of Historic Places
by the United States
Department of the Interior

Erected 1972.

Topics. This historical marker is listed in these topic lists: Colonial Era • Notable Buildings. A significant historical year for this entry is 1797.

Location. 38° 54.36′ N, 77° 4.13′ W. Marker is in Northwest Washington in Washington, District of Columbia. It is in Georgetown. It is on Prospect Street Northwest east of 35th Street Northwest, on the right when traveling west. Touch for map. Marker is at or near this postal address: 3425 Prospect Street Northwest, Washington DC 20007, United States of America. Touch for directions.

Regionally, this marker is in the Washington Metropolitan Area.

It is also in the American Northeast,

in the Upper South,

in the Mid-Atlantic,

in the Tidewater,

and in the Chesapeake Bay Region.

Globally, it is in North America,

the Western Hemisphere,

the Western World,

and the Anglosphere.

Other nearby markers. At least 8 other markers are within walking distance of this marker: Prospect House (within shouting distance of this

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marker); Halcyon House (within shouting distance of this marker); Houses With A Prospect (within shouting distance of this marker); a different marker also named Halcyon House (about 300 feet away, measured in a direct line); Holy Trinity Church (about 400 feet away); Hollywood on the Potomac (about 400 feet away); Dedicated to the Memory (about 400 feet away); The Exorcist Steps (about 400 feet away). Touch for a list and map of all markers in Northwest Washington.

More about this marker. This property is also known as Quality Hill, the John Thomson Mason House or the Worthington House.

Also see . . . Quality Hill - The John Thomson Mason House.
This form shares the historical significance of the house on page 3:

The Joint Committee on Landmarks has designated "Quality Hill" (the John Thomson Mason House) a Category II Landmark of importance which contributes significantly to the cultural heritage and visual beauty of the District of Columbia. "Quality Hill" is one of the finest of the few surviving large, free-standing late-Georgian townhouses of Georgetown. It was built around 1797-98 and first occupied by John
Photographed by Devry Becker Jones (CC0), February 12, 2018

2. 3425 Prospect Street NW Marker
Thomson Mason. From its first to its present owner, Quality Hill has been occupied by individuals prominent in local and national affairs.

(Submitted on February 12, 2018, by Devry Becker Jones of Washington, District of Columbia.)

3425 Prospect Street NW image. Click for full size.

Photographed by Devry Becker Jones (CC0), February 12, 2018

3. 3425 Prospect Street NW

Quality Hill - The John Thomson Mason House image. Click for full size.

Photographed by J. Makali Bruton, March 23, 2025

4. Quality Hill - The John Thomson Mason House

Credits. This page was last revised on March 23, 2025. It was originally submitted on February 12, 2018, by Devry Becker Jones of Washington, District of Columbia. This page has been viewed 637 times since then and 37 times this year. Photos: 1. submitted on March 23, 2025, by J. Makali Bruton of Washington, District of Columbia. 2, 3. submitted on February 12, 2018, by Devry Becker Jones of Washington, District of Columbia. 4. submitted on March 23, 2025, by J. Makali Bruton of Washington, District of Columbia. • Bill Pfingsten was the editor who published this page.