According to Official Guinness Records,
The largest city ever to host a Winter Olympic Games is Vancouver, Canada with a population of 2,116,581 people who hosted the XXI Winter Olympiad from 12-28 February 2010. The previous record holder was Turin (Torino) the host of the 2006 games, who had a population of 1.7 million.
For a complete list of 2010 records, please visit 2010 Guinness Records in Canada.