Why is it der Steirer?

Steirer ends in -er, and most nouns ending in -er are masculine: in a German dictionary, 86% of them take der.

All nouns ending in -er
Sense 1
der

Meaning

[1] residents of Styria

[1] Einwohner der Steiermark

[2] Members of the Styrian State People

[2] Angehöriger des steirischen Landesvolkes

Examples

[1] Arnold Schwarzenegger is born in Styria

[1] Arnold Schwarzenegger ist gebürtiger Steirer.

Declension

1 Singular Plural
Nominativ der Steirer die Steirer
Genitiv des Steirers der Steirer
Dativ dem Steirer den Steirern
Akkusativ den Steirer die Steirer

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary