Chapelle Forerie, Former tide-mill chapel in Indre, France

Chapelle Forerie is a former tide mill converted into a chapel on the Île d'Indret in Indre, Loire-Atlantique. Its rough gray-brown walls rise to a stepped gable, with a tall arched panel reading "Chapelle à marées" on the facade. Three tall arched windows with pale opaque glass line the side wall, and a low metal fence runs along the base.

In 1777 the Navy Minister Antoine de Sartine had a cannon foundry built on the Île d'Indret, with English metallurgists from the Wilkinson family. Cannons were cast solid, then bored and reamed in the neighbouring forerie, powered by a tide mill on the south arm of the Loire. Steam engines replaced the mill from 1810, and in 1842 the building became a neo-Gothic chapel, the first in Loire-Inférieure.

The chapel shows how faith and industrial work were connected in this region. Visitors can see how a space for prayer and a workspace existed side by side for the same community.

The chapel stands on the former river island of Indret, in the commune of Indre on the left bank of the Loire estuary. It is owned by the town of Indre since 2001 and was listed as a monument historique on 21 November 2022, floor, timber vault and light fittings included. Look for the arched panel reading "Chapelle à marées" on the facade.

Archaeological digs by volunteers of Indre Histoire d'Îles from 1998 to 2002 uncovered the tide mill's remains beneath the chapel floor. The mill had been fitted as a retention basin closed by two dikes and fed by falling tides.