Vienna, OntarioVienna is an unincorporated community in the Elgin County of Ontario, Canada. It is recognized as a designated place by Statistics Canada.DemographicsIn the 2021 Census of Population conducted by Statistics Canada, Vienna had a population of 736 living in 235 of its 249 total private dwellings, a change of from its 2016 population of 773. With a land area of, it had a population density of in 2021.