Dubuque is a city in Dubuque County, Iowa, United States. It is the principal city of the Dubuque Metropolitan Area which encompasses all of Dubuque County. As of the 2000 census, the city had a population of 57,686. But, recent studies show major expansion of Dubuque, raising the population to 61,422 by the 2005 census. It is the county seat of Dubuque CountyGR6. Dubuque is located on the Mississippi River. The city is the center of a small metro area known locally as "The Tri-State Area." It is located at the point where Iowa, Wisconsin and Illinois meet. Adjacent towns include Asbury, Sageville, Key West and Peosta, Iowa, and East Dubuque, Illinois.

The city is located at the junction of U.S. Highways 20, 61 , 52 and 151, and Iowa Highway 3. It is served by the Chicago Central and Pacific Railroad (a subsidiary of the Canadian National Railway), the BNSF Railway, and the Iowa, Chicago and Eastern Railroad. American Airlines provides service between Dubuque and O'Hare International Airport in Chicago from the Dubuque Regional Airport, located about seven miles south of Dubuque along U.S. Highway 61. Dubuque is often called "The Key City." It is also known as the City of Five Flags for the five different flags — English, Spanish, Royal French, Republican French, and American — which since the 1600s have flown over the land on which Dubuque now sits.