- Apr 3 Adolf Rzepko, Polish composer, born in Prague, Kingdom of Bohemia (d. 1892)
- Apr 5 David Rumph Jones, American Major General (Confederate Army), born in Orangeburg, South Carolina (d. 1863)
- Apr 11 Ferdinand Lassalle, French socialist and political activist (Allgemeiner), born in Breslau, Prussia (d. 1864)
- Apr 13 Thomas D'Arcy McGee, Irish-Canadian journalist and Father of Confederation, born in Carlingford, County Louth, Ireland (d. 1868)
- Apr 25 Charles Dowd, American principal who was the 1st to propose standardized time zones (for America's railways), born in Madison, Connecticut (d. 1904)
- Apr 28 James Winning McMillan, American Brevet Major General (Union Army), born in Clark County, Kentucky (d. 1903)
Greatest Generation
Silent Generation
Baby Boomer
Generation X
Millennial
Generation Z