The capital city formed from the historic districts of Buda and Pest is Budapest.
Budapest sits on both banks of the Danube in Hungary. Buda occupies the hilly western bank, including Castle Hill and the former royal centre, while Pest spreads across the flatter eastern bank. The two sides are linked by famous bridges, including the Chain Bridge.
Modern Budapest was created in 1873 through the administrative unification of Buda, Pest and Óbuda. Óbuda, meaning “Old Buda,” was a separate historic settlement farther north and is an important part of the city’s origin story even though it is often omitted from the short version of the answer.
Buda and Pest had distinct historical identities for centuries. Buda became the royal capital of the Kingdom of Hungary in 1361, while Pest developed into a major commercial and civic centre. After unification, Budapest became a leading city of the Austro-Hungarian Empire. A common mistake is to treat Buda as the whole western half of the city and Pest as the entire capital; together with Óbuda, they form Budapest.