Located in the heart of the Py Valley, north of the Marne.
In 1219, the village was called Sancta Maria Api. It was in 1276, four different pontificates that same year, he became Santa Maria ad Pinum, and remained so until 1384.
In 1793, the village became Montagne Py then Val Aumont.
Since 1804, the town resumed its name Sainte Marie to Py.