Editing St. Mary's County, Maryland (section)

==Geography==
According to the [[U.S. Census Bureau]], the county has a total area of {{convert|764|sqmi}}, of which {{convert|357|sqmi}} is land and {{convert|407|sqmi}} (%) is water.<ref name="GR1">{{cite web|url=https://www.census.gov/geo/maps-data/data/docs/gazetteer/counties_list_24.txt|publisher=United States Census Bureau|access-date=September 14, 2014|date=August 22, 2012|title=2010 Census Gazetteer Files|url-status=dead|archive-url=https://web.archive.org/web/20140913171515/http://www.census.gov/geo/maps-data/data/docs/gazetteer/counties_list_24.txt|archive-date=September 13, 2014}}</ref> It is the second-largest county in Maryland by total area.

Located on the [[St. Mary's Peninsula]], St. Mary's County is largely bordered by water: the [[Patuxent River]] (northeast), the [[Chesapeake Bay]] (east), the [[Potomac River]] (southwest), and the [[Wicomico River (Potomac River)|Wicomico River]] (west). Its coastline has many coves, tidal creeks, bays, and inlets. Many coastal areas are made up of mixed clay-and-sand cliffs and bluffs, which protect many parts of the county from storm surges, however, there are low-lying coastal areas with coarse sand or gravel beaches or tidal marshlands, as well. The county has a tiny exclave on the other side of the Potomac river due to the Maryland-Virginia border cutting through a beach near the little wicomico river.

The interior of much of the county is hilly to varying degrees, with forests and agricultural fields. There also are coastal plain areas, much of which are under agriculture or under new development. Residential development has been increasing steadily for decades.

The county's very extensive waters are mostly [[brackish]], ranging from significant degrees of saltwater in tidal areas that are on or near the Chesapeake Bay, to a greater predominance of freshwater and lower-salt-concentrations in its interior tidal waterways and also further up its bordering rivers.

===Climate===
According to the [[Köppen climate classification]], the county has a [[humid subtropical climate]] (''Cfa''.) According to the [[Trewartha climate classification]], the climate is ''Cf'' or [[oceanic climate|oceanic]] (''Do'') depending on whether eight or seven months average above {{convert|50|°F|°C|abbr=on}},) respectively. Average monthly temperatures in Leonardtown range from 36.3&nbsp;°F in January to 78.1&nbsp;°F in July.<ref>{{cite web | url=https://prism.oregonstate.edu/explorer/ | title=PRISM Climate Group at Oregon State University }}</ref>

===Adjacent counties===
*[[Calvert County, Maryland|Calvert County]] (northeast)
*[[Charles County, Maryland|Charles County]] (northwest)
*[[Somerset County, Maryland|Somerset County]] (southeast)
*[[Northumberland County, Virginia]] (South)
*[[Westmoreland County, Virginia]] (southwest)
*[[Dorchester County, Maryland|Dorchester County]] (east)

St. Mary's County borders [[Virginia]], across the Potomac River.<ref name="nsglc.olemiss.edu">"Supreme Court Rules for Virginia in Potomac Conflict: Virginia v. Maryland, 124 S.Ct. 598," 2003 LEXIS 9192 (2003), The National Sea Grant Law Center, http://nsglc.olemiss.edu/SandBar/SandBar2/2.4supreme.htm"</ref> St. Mary's County waters also are bordered by Virginia's territorial waters in Potomac tributary mouths on the Virginia side,<ref name="nsglc.olemiss.edu"/> tidal interface zones,<ref name="nsglc.olemiss.edu"/> and the Chesapeake Bay.<ref>"Virginia-Maryland Boundary for Chesapeake Bay/Eastern Shore", Virginiaplaces.org, http://www.virginiaplaces.org/boundaries/mdboundarycbay.html</ref> Sometimes, water rights in all of these areas are still disputed.<ref name="nsglc.olemiss.edu"/><ref>"Modern Maryland-Virginia Boundary Disputes" Virginiaplaces.org, http://www.virginiaplaces.org/boundaries/mdboundarymodern.html</ref>