On November 24, 1917 a bomb thought to have been planted by anarchists killed nine police officers in Milwaukee, Wisconsin.
On June 2, 1919, anarchists were suspected of setting off a series of bombs in eight cities, including Washington, D.C., where a bomb partially destroyed the home of Attorney General A. Mitchell Palmer.
On September 16, 1920, an explosive-laden wagon exploded on Wall Street, across from the headquarters of J.P. Morgan & Company, killing 40 and wounding 300.
In 1886 at Haymarket Square in Chicago during a labor rally bombings killed many.
In 1910 at the Los Angeles Times Building during a labor dispute a bomb killed 20.
In 1963 at Birmingham Alabama's 16th Street Baptist Church 4 little girls were killed and 22 injured in a terrorist attack.
In the first century Jews committed terrorist acts of terrorism trying to overthrow the Roman rule of Palestine
Then there was the IRA and the "Real IRA"
Assasinations and terrorist acts by those fighting colonialism. An example was the killing of the archduke Franz Ferdinand in Sarajevo, Bosnia.
Basques, Irish, Quebecois, and African and Latin American revolutionaries used terror as a tactic.
In 1605 Swift action by British intelligence services foil an imminent terrorist strike by religious extremists led by Guy Fawkes that would have resulted in mass death and social upheaval on an unprecedented scale.
Editorisl regarding 1605 and 2006 http://www.truthout.org/docs_2006/081806Z.shtml