- Apr 4 Heinrich Wilhelm Dove, Prussian physicist and meteorologist, dies at 75
- Apr 8 Anthony Panizzi, Italian patriot, writer, and English librarian (British Museum, 1831-66), dies at 81
- Apr 9 Ernst Richter, German musical theorist and composer, dies at 70
- Apr 16 Bernadette of Lourdes [Bernadette Soubirous], French saint (saw Virgin Mary at Lourdes), dies from tuberculosis at 35 in Nevers, France
- Apr 18 Anthony Pannizi, Italian-born British librarian (British Museum), dies at 81
- Apr 29 Douglas H. Cooper, American Brigadier General (Confederate Army), dies at 63
- Apr 30 Emma Smith, Inaugural President of the Women's Relief Society of The Church of Jesus Christ of Latter-day Saints, dies at 74
- Apr 30 Sarah Josepha Hale, American writer (Mary Had a Little Lamb), editor, activist, and founder of the Seaman's Aid Society of Boston, dies at 90
Assassination
Drug Overdose
Gunshot Wound
Murder
Plane Crash
Suicide