Editing Adelphi, Maryland (section)

==History==
The unincorporated Adelphi community takes its name from the historic [[Adelphi Mill]], established in 1796 along the [[Northwest Branch Anacostia River|Northwest Branch]] of the [[Anacostia River]]. and continues to attract visitors and can be rented for special functions. During the 19th century, [[George Washington Riggs]] acquired much of the area northeast of [[Washington, D.C.]], as his Green Hill estate in the [[Chillum, Maryland|Chillum Manor]] district. That estate included present-day Adelphi. In the early 1920s, part of the area was acquired by [[Leander McCormick-Goodhart]] as part of his [[Langley Park, Maryland|Langley Park]] estate.<ref>"Adelphi Mill Is Reopened to the Public," ''The Washington Post and Times-Herald'', Dec 6, 1954, pg. 21.</ref> Labor organizer [[Mary Harris Jones|Mary Harris "Mother" Jones]] died in 1930, at the farm of Walter and Lillie May Burgess near Powder Mill and Riggs Roads in present-day Adelphi. A marker was erected by the [[Maryland State Highway Administration]] commemorating Mother Jones at her death site. Unlike its nearby neighbors [[Hyattsville, Maryland|Hyattsville]] and [[College Park, Maryland|College Park]], the area remained relatively undeveloped until immediately following [[World War II]]. At that time, subdivisions quickly developed.

To distinguish it from the other neighboring unincorporated communities of [[Lewisdale, Maryland|Lewisdale]] and [[Langley Park, Maryland|Langley Park]], the growing subdivisions banded together in the mid-1950s and adopted the name "Adelphi" to reflect their commitment to the preservation of the historic mill of the same name. A community focal point that originally developed in the late 1950s is the Adelphi Pool, a private pool in the Adelphi neighborhood, located next to George Washington Cemetery on Riggs Road.

Use of the Adelphi Pool requires paid membership or being accompanied by a member and paying a small fee. The Adelphi pool offers swimming lessons and also features swim teams which compete against each other. Two notable features of the Adelphi Pool are its long water slide and basketball hoop.

In 1971, the [[Harry Diamond Laboratories]] was established on {{convert|137|acre|km2}} in the northern part of Adelphi. That facility continues as the Adelphi Laboratory Center, [[Army Research Laboratory]] (ARL), the U.S. Army's corporate research laboratory.<ref name="gsec">{{cite web| url=http://www.globalsecurity.org/military/facility/adelphi.htm| title=Adelphi Laboratory Center |date=2008-04-15| work=Entry for Adelphi Laboratory Center [Harry Diamond Laboratories], US Army Research Laboratory (ARL)| publisher=Globalsecurity.org}}</ref> Other adjacent federal facilities include the [[National Archives at College Park]] and headquarters of the [[Food and Drug Administration]].

===Historic sites===
The following is a list of historic sites in Adelphi identified by the [[Maryland-National Capital Park and Planning Commission]]:<ref>[http://www.mncppc.org/county/historic_sites.htm M-NCPPC Illustrated Inventory of Historic Sites (Prince George's County, Maryland), 2006] {{Webarchive|url=https://web.archive.org/web/20080725020708/http://www.mncppc.org/county/historic_sites.htm |date=2008-07-25 }}.</ref>
{|class="wikitable sortable" style="width:98%"
! {{NRHP color}}|
! width = 25% {{NRHP color}}| '''Site name'''
! width = 8% class="unsortable" {{NRHP color}}| '''Image'''
! {{NRHP color}}|'''Location'''
! class="unsortable" {{NRHP color}}| '''M-NCPPC Inventory Number'''
! class="unsortable" {{NRHP color}}| '''Comment'''
|--
! {{NRHP color}} | <small>1</small>
| [[Adelphi Mill|Adelphi Mill and Storehouse]]
| [[File:Adelphi Mill 1.jpg|border|125px|center]]
| 8401 and 8402 Riggs Road
| 65-006
| <!-- Comment goes here -->
|--
! {{NRHP color}} | <small>2</small>
| [[Cool Spring Farm (Miller’s House)]]
| <!-- Image goes here -->
| 2201 Cool Spring Road
| 65-005
| <!-- Comment goes here -->
|--
! {{NRHP color}} | <small>3</small>
| [[Gallant House (Adelphi, Maryland)|Gallant House]]
| <!-- Image goes here -->
| 3124 Powder Mill Road
| 61-013
| <!-- Comment goes here -->
|}