 The U.S. Bureau of Economic Analysis combines the city of Petersburg with the cities of Colonial Heights and Hopewell, and neighboring Dinwiddie and Prince George counties for statistical purposes.Petersburg is also a part of the Tri-Cities regional economy known as the "Appomattox Basin", which includes a portion of southeastern Chesterfield County.As of the 2010 United States Census, there were 32,420 people living in the city.