New Vienna is a city in Dubuque County, Iowa, United States. It is part of the Dubuque, Iowa Metropolitan Statistical Area. The population was 400 at the 2000 census. New Vienna is home to the Saint Boniface Catholic Church. The city promotes itself with the slogan The eNVy of Iowa. New Vienna is located at 42Â°32â²54â³N 91Â°06â²49â³W / 42.548404Â°N 91.113568Â°W / 42.548404; -91.113568 (42.548404, -91.113568). According to the United States Census Bureau, the city has a total area of 0.4 square miles (1.2 km2), all of it land.