In the south, Moosburg borders the municipalities of Pörtschach and Krumpendorf, both popular bathing resorts on the northern shore of Lake Wörth.

The Old High German name moos ("mire") refers to several swamps and ponds around the settlement, remnants of the last glacial period and today a protected area.

The municipal area comprises the cadastral communities of Bärndorf, Gradenegg, Kreggab, Moosburg, Sankt Peter, Seigbichl (Žihpolje), Tigring (Tigrče), and Tuderschitz (Tudrešiče).

Arnulf of Carinthia, the Carolingian king of East Francia and Holy Roman Emperor, grew up here and used the castle as a Kaiserpfalz residence.

Part of the Duchy of Carinthia from 976, the Moosburg estate was later held by the noble House of Gorizia (Görz) which finally lost their remaining Carinthian possessions to the Habsburg emperor Frederick III about 1460.