The city belongs to the mesoregion Metropolitana de Belo Horizonte and to the microregion of Belo Horizonte and has a territorial extension of 195.2 km² and borders the municipalities of Ribeirão das Neves, Esmeraldas, Betim, Ibirité and Belo Horizonte. The elevation of the city hall is 939 meters.
According to estimates from 2005 the municipal population was 591,518 making it the second most populous city in the state of Minas Gerais, after Belo Horizonte.
The population is very young with 86% of the population being less than 50 years old.
Contagem is primarily a city of heavy industry with a diversified industrial complex; even though minerals processing and chemicals still have a large importance. The municipality is responsible for 4.2% of the state GDP, occupying second place after Belo Horizonte. Serious problems with both water and air pollution exist and the Pampulha Lake receives large quantities of heavy metals from the city.
Contagem was the first industrial district built in Minas. Inaugurated in 1946, by 1950 it was the largest in the state. The Gafanhoto power plant (on the Pará River) was built by the State government in 1952 to provide for the implementation and development of the district, which is still the largest industrial region in Minas Gerais.
Ceasa Minas Greater BH (regional wholesale supply center) is located in Contagem. It has a built area of 605,000 sq. mts., with 535 companies installed, and a public on busy days of 65,000 people. It is the largest in vegetables in all of Brazil.