St Mary's, Isles of Scilly

St Mary's
Porthcressa, showing part of Hugh Town
St Mary's
Location within Isles of Scilly
Area6.58 km2 (2.54 sq mi)
Population1,723 (2011)
 Density262/km2 (680/sq mi)
OS grid referenceSV915115
Civil parish
  • St Mary's
Unitary authority
Ceremonial county
Region
CountryEngland
Sovereign stateUnited Kingdom
Post townISLES OF SCILLY
Postcode districtTR21
Dialling code01720
PoliceDevon and Cornwall
FireIsles of Scilly
AmbulanceSouth Western
UK Parliament

St Mary's (Cornish: Ennor, lit.'The Mainland') is the largest and most populous island of the Isles of Scilly, an archipelago off the southwest coast of Cornwall in England, United Kingdom.