- Jun 1 US adventurer William Walker conquers Nicaragua, reestablishes slavery
- Jun 2 The Portland Rum Riot occurs in Portland, Maine
- Jun 5 Anti-foreign anti-Roman Catholic Know-Nothing Party's 1st convention
Music Premiere
Jun 13 Giuseppe Verdi's opera "Les vêpres sicilenne" (The Sicilian Vespers) premieres at the Paris Opéra