There's more than one place called '''Londonderry''':
Londonderry (New South Wales) - a suburb of Sydney
Londonderry (Nova Scotia)
Londonderry (Chile) - an island in Tierra del Fuego
County Londonderry (County Derry) - in Northern Ireland
'''Londonderry''' - see '''Derry''' - a city in Northern Ireland
Londonderry (North Yorkshire) - a village in North Yorkshire, England
Londonderry (New Hampshire) - a town in New Hampshire, New England.
Londonderry (Vermont) - a town in Windham County (Vermont), Vermont, New England.