The town is located 20 km northeast of Bourg-en-Bresse, in the foothills of the Jura.
The upper village of Treffort is located in Revermont, and the lower part en Bresse. The history of this village was torn for centuries. Indeed, first under Burgundian domination, it was from 1289 under Savoyard domination until the seventeenth century, when the department of Ain became definitively French. Formerly mainly vineyards, crops are currently located in the plain. A small industry and many shopkeepers and craftsmen ensure the life of the city. The village keeps many traces of this turbulent history, including its fortified architecture, its castle, its church, its halls, its hospital, or the many small houses built with the stones of the castle, which can be observed through many re-employment in the village houses.
Located at the foot of Mount Myon, on the road that connects Revermont Treffort Coligny, Pressiat is essentially a small agricultural center. But the example of other villages in this region, many side retirees and residents settled there.