As of 2007, the town of Pétange, which lies in the north of the commune, has a population of 7,399. Other towns within the commune include Lamadelaine and Rodange. The commune is one of the smallest communes of Luxembourg, yet is the fifth-most populous. It is the most-populous commune without city status.
In 1601, the boundary between Luxembourg and the Duchy of Lorraine was definitively demarcated for the first time. The modern commune was divided between the two, with the town of Pétange going to Luxembourg, but the towns of Rodange and Lamadelaine, which are further to the south, lying on the Lorrainian side of the border.
When, in 1795, Luxembourg was annexed into Revolutionary France as part of the département of Forêts, its former territories were reunited, and the commune's territory was established as it is today. However, when Luxembourg passed to the United Kingdom of the Netherlands, after the Congress of Vienna, the towns of Rodange and Lamadelaine passed with it.
The town's importance grew greatly in the late nineteenth century, thanks to the booming iron-mining and steel industries. The first railway into Pétange was opened in 1873, running to Esch-sur-Alzette. Further railway lines were added to Ettelbruck (1873) and Luxembourg City (1900).
On 9 September 1944, Pétange became the first commune in the country to be liberated by Allied soldiers at the end of the German occupation in the Second World War. In remembrance to the first soldier to die in the liberation, a memorial was erected in his honor: Hyman Josefson Square.
The commune is only 12 km² in area, one of the smallest in Luxembourg, but is the site of three significant towns. The town of Pétange itself has a population of 6,909, but, despite being the seventh-largest town in Grand Duchy, accounts for under half of the population of the commune. Rodange, in the south-west of the commune, is home to 4,505 people, whilst Lamadelaine, in the south of the commune, has a population of 2,335.
The south of the commune is home to Titelberg, a prominent hill on top of which lie the ruins of a Celtic oppidum. The walled hill fort was 1 km (0.6 miles) long. The entire settlement had a total population of 10,000 before the Roman conquest, making it the largest pre-Roman settlement in Luxembourg.
The 'Fond de Gras' heritage railway and museum recreate the conditions of the Red Lands in the year 1900, at the height of their growth and development. Whilst the centre lies just within the commune of Differdange, to the east, the two steam locomotives take visitors to the towns of Pétange and Rodange, and provide a stream of tourists to the towns in the summer.
Pétange has a football team in Luxembourg's top-flight National Division, called CS Pétange. They play their home games at the Stade Municipal. Despite being one of the oldest Luxembourgian clubs in existence, having been founded in 1910, Pétange have one only one trophy, the Luxembourg Cup in 2004-05.