Triadelphia

HISTORICAL POPULATED PLACE · MARYLAND

A historical populated place in Montgomery County, Maryland, recorded by the U.S. Geological Survey's Geographic Names Information System.

Location Record

Name: Triadelphia
Feature Type: Populated Place (historical)
State: Maryland
County: Montgomery County
USGS Map: Sandy Spring
Coordinates: 39.2334391, -77.0413674
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GNIS Feature ID: 598518

Names and historical notes

Recorded by GNIS. Source wording is retained; these notes have not been independently verified by Forgotten America.

GNIS historical note

Mill town built in 1809, inundated in 1931 by Triadelphia Reservoir

Source editions and recorded citations

Feature ID 598518. Description/History extract: August 28, 2026. All Names extract: September 30, 2026. Retrieved October 22, 2026. Only populated fields are displayed.

GNIS citation text may identify a source series rather than a specific page. It is reproduced below without implying that its underlying documents were inspected.

Map U.S. Geological Survey U.S. Department of the Interior, U.S. Geological Survey, 1:62,500-scale topographic maps; various edition dates. Represents new or changed names from published editions. Map name and year of publication follow (if known):

GNIS source datasets and documentation

Source: U.S. Geological Survey Geographic Names Information System (GNIS), Historical Features.