Why is it das Oldenburg?

No ending, compound or meaning rule gives away the article of Oldenburg, so learn the two together: das Oldenburg.

Sense 1
das

Meaning

[1] A big city in northern Germany

[1] eine Großstadt in Norddeutschland

[2] Earlier land of the German Empire

[2] früheres Land des Deutschen Reiches

Examples

[1] Oldenburg is located west of the Wesä

[1] Oldenburg liegt westlich der Weser.

[1] The medieval Oldenburg

[1] Das mittelalterliche Oldenburg
More source examples (1)

These dictionary examples can include historical and less common uses.

[2] Eutin used to belong to Oldenburg

[2] Eutin gehörte früher zu Oldenburg.
Grammar note

The article is needed if "Oldenburg" in a certain quality, at a certain time or period as a subject or object in the sentence, is otherwise, i.e. usually, no article is used.

Declension

1 Singular Plural
Nominativ (das) Oldenburg —
Genitiv (des Oldenburg) (des Oldenburgs) Oldenburgs —
Dativ (dem) Oldenburg —
Akkusativ (das) Oldenburg —

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary