county seat in Anne Arundel County, Maryland, USA and Maryland federated state capital city.
According to the U.S. Census Bureau, the county has a total area of 588 square miles (1,520 km2), of which 415 square miles (1,070 km2) is land and 173 square miles (450 km2) (29%) is water. Anne Arundel County is located to the south of the city of Baltimore.
Most of the county’s borders are defined by water. To the east lies the western shore of the Chesapeake Bay, and numerous tidal tributaries of the Bay indent the shoreline, the various rivers, creeks, streams, inlets forming prominent peninsulas, also known as “necks” (as further south in Virginia). The largest of these tributaries include (from north to south), the Magothy River, Severn River, South River, and the West River. Further south, the upper Patuxent River forms the border of Anne Arundel with Prince George’s County to the west. Deep Run forms part of the northwestern border with Howard County, and Lyons Creek forms part of the southern border with Calvert County. The Patapsco River to the north is the border with Baltimore County, but the communities and areas of Brooklyn and Curtis Bay neighborhoods (and adjacent Fairfield, Wagner’s Point [also known as East Brooklyn], Arundel Cove [off of Curtis Creek], and Hawkins Point), lying south of the Patapsco River were annexed from Anne Arundel County to Baltimore City in the third major annexation of January 1919.
Anne Arundel County originally included all of the land between the Patuxent River and the Patapsco River (mainstem and South Branch) upstream to their headwaters on Parr’s Ridge. The northwestern section of this long tract later became Howard County, with the border between the two running very close to the Atlantic Seaboard fall line. As a result, Anne Arundel County lies almost entirely within the Atlantic Coastal Plain while Howard County is almost entirely within the Piedmont province.
Elevations in Anne Arundel County range from sea level at the Chesapeake and tidal tributaries to approximately 300 feet (91 m) in western areas near the fall line.The terrain is mostly flat or gently rolling, but more dramatic banks and bluffs can be found where waterways cut through areas of higher elevation.
With the exception of the very limited extent of Piedmont underlain by Precambrian to early Paleozoic metamorphic rock, all of the county is underlain by thick deposits of gravel, sand, silt, and clay dating from the early Cretaceous to Holocene times.Most of these sediments are unconsolidated but include local formations of sandstone, especially in the Pasadena area.