April 21, 1838John Muir, Pioneering Conservationist and Founder of Yosemite National Park, Born in Dunbar.
April 21, 1874Walter Wilson, Mechanical Engineer, Designer of Cars and Tanks, Is Born in Blackrock, Co. Dublin
April 21, 1907The Nationalist Groups, Cumman Na NGaedheal and Dungannon Clubs, Combine to Form the Sinn Féin (Ourselves) League
April 21, 1912The Aud Arrives at Banna Strand, Co. Kerry, From Germany With 20,000 Rifles for Use of the Volunteers in the Easter Uprising