Direct answer: The river that passes through Budapest is the Danube (Danube River).
Context and quick notes:
- The Danube flows through Budapest from north to south and has historically caused significant flooding in the city during high-water events.[1][2][3]
- Recent European flood events around Budapest have involved the Danube reaching decade highs and prompting protective measures, especially during storms like Boris in 2024, with authorities building sandbag defenses along the river.[4][5][7]
If you’d like, I can pull the latest updates from reliable outlets and summarize the current flood status in Budapest, including water levels and any travel advisories.