- Mar 2 15th Grand National: Tom Oliver aboard Peter Simple wins his third GN Steeplechase and the stallion's second; oldest horse to win event at 15
- Mar 2 Territory of Washington organized after separating from Oregon Territory
- Mar 3 Transcontinental railroad survey is authorized by US Congress
- Mar 3 US Assay Office in NYC authorized
- Mar 4 Pope Pius IX recovers Catholic hierarchy in Netherlands
- Mar 4 William Rufus de Vane King (D) sworn in as 13th US vice-president
Steinway & Sons Piano
Mar 5 Piano company Steinway & Sons founded by Heinrich Steinweg (later Henry Steinway) in New York City
La Traviata
Mar 6 Giuseppe Verdi's opera "La Traviata" premieres at Teatro La Fenice in Venice, Italy
The Provincial Freeman
Mar 24 Anti-slavery newspaper "The Provincial Freeman" first published in Windsor, Ontario, edited by Samuel Ringgold Ward and Mary Ann Shadd Cary, first black woman publisher in North America
Authors
Civil Rights Activists
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Kings
Revolutionaries
Scientists