"Reservations for eastern Europe have soared this year because Americans want more for their money," said Mike Pina, spokesman for the American Automobile Association (AAA), one of the largest tour operators and travel agents in the United States.
This summer, bookings made at AAA agencies for eastern European destinations climbed 55 per cent, according to a poll.
Bookings for the former Yugoslav republic of Croatia climbed by 69 per cent, for Hungary by 76 per cent and for Poland by 10 per cent.
Slovenia, which adopted the euro at the beginning of the year, saw a 100-per cent rise in bookings by US tourists, but the grand prize went to new European Union member Romania, where bookings rose seven-fold.
But Americans have not been entirely dissuaded by the strong euro from visiting Europe.
For the 12 months from August 2006, before dollar-euro exchange rate began to bite, bookings to Italy and France were both up more than 13 per cent.
Reservations to England and Scotland rose by a more modest 2.5 per cent and 4.6 per cent, compared to the same period a year earlier.
"Americans love Western Europe, and the UK, France and Italy continue to be top destinations," said Sandy Hughes, vice-president of AAA Travel.
"But many are choosing to visit countries where the dollar stretches further and the crowds are lighter," she added.