- April 1, 1434 - Yury of Zvenigorod arrived in Moscow and again declared himself the Grand Prince.
- April 8, 1783 - The Crimean Khanate was incorporated into the Russian Empire.
- April 20, 1876 - April Uprising of 1876: Bulgarian nationalists attacked the Ottoman police headquarters in Oborishte.
- April 28, 1920 - With the Azerbaijani capital Baku under Eleventh Army occupation, the parliament agreed to transfer power to the Communist government of the Azerbaijan SSR.
- April 30, 1975 - Fall of Saigon: The South Vietnamese capital of Saigon was captured by the People's Army of Vietnam.