Tourism Minister Mary Hanafin travelled to the US to promote the database, which helps people explore their ancestry.

"Launching the last full Irish census online, dating from 1901, will encourage more people to look at their history and ancestors," said Ms Hanafin.

The census, launched in Ireland earlier this month, has already attracted the interest of more than three quarters of a million people worldwide and tens of millions of hits. It follows the earlier successful launch of information from the 1911 document.

Ms Hanafin believes promoting the database to the Irish diaspora could bring thousands more tourists to Ireland.

"Being able to see the actual return, completed on census night in March 1901 by your blood relatives, can be a truly emotional moment for many," she said.

"We know that when the 1911 census went online there was huge interest from across the globe. This even older census will open up another chapter in people's efforts to trace their roots."

The Tourism Minister will meet actor Gabriel Byrne, Ireland's first cultural ambassador, industry figures and media representatives during her visit.

More than 250 US travel writers will also be invited to Ireland as part of the campaign.

Almost 40 million people living in the US claim Irish ancestry.