- Mar 1 Major League Baseball Rules Committee rule that pitcher's mound must not be more than 15 inches higher than the baselines or home plate
Event of Interest
Mar 2 Martha Washington Hotel, catering to women only, opens in NYC

Martha Washington
- Mar 3 North Carolina becomes 1st state requiring registration of nurses
- Mar 4 Stanley Cup, Montreal Arena, Westmount, Quebec: Montreal HC beats Winnipeg Victorias, 4-1 for a 2-1 challenge series victory
- Mar 5 Definitive treaty for construction of Baghdad railway drawn up
- Mar 10 Harry Gammeter, Cleveland, patents multigraph duplicating machine
- Mar 12 NY Highlanders (Yankees) approved as members of AL
- Mar 13 Fall of the Sokoto Caliphate in Northern Nigeria, the British claim supremacy on over 500,000 square miles
- Mar 14 1st national bird reservation established in Sebastian, Florida
- Mar 14 Stanley Cup, Dey's Arena, Ottawa, Ontario: Ottawa HC beats Rat Portage Thisles, 4-2 for a 2-0 challenge series sweep
- Mar 14 WB Yeats & Lady Gregory's "Hour-glass" premieres in Dublin
- Mar 18 Following through on its attacks on Roman Catholic institutions, the French Government dissolves the Catholic religious orders
- Mar 22 NY Highlanders (Yankees) tickets 1st go on sale
- Mar 22 Niagera Falls runs out of water because of a drought
Event of Interest
Mar 22 US Anthracite Coal Commission, set up by President Theodore Roosevelt, submits its recommendations for shorter hours, a 10-per cent wage increase, and an 'open shop'

Theodore Roosevelt
- Mar 23 The Wright brothers 1st file a patent for a flying machine, which is granted 3 years later
- Mar 25 Racing Club de Avellaneda, one of the big five of Argentina, is founded.
- Mar 26 American Hotel opens in Amsterdam
- Mar 27 65th Grand National: Percy Woodland aboard 13/2 chance Drumcree wins by 3 lengths from Detail
- Mar 31 Richard Pearse flies a monoplane several hundred yards in New Zealand