Réserve naturelle régionale de la tourbière de la Grande Pile, Regional nature reserve in Saint-Germain, France

The Réserve naturelle régionale de la tourbière de la Grande Pile is a 59.27-hectare protected area in Saint-Germain, Haute-Saône, made up of three separate parts: the crescent-shaped peat bog itself, a section of the Bois de Question to the northeast and the northern end of the Étang du Grand Saint-Maurice to the southeast. Most of the land is wooded, with open water, floating mats of yellow-green plants, thin dead trunks and marshy edges. All stages of a peat bog occur here, from acidic fen to a birch wood on peat.

Mining operations for peat extraction began here in 1866, but the site was later protected as a natural area. In July 2016, it gained official status as a regional nature reserve.

The bog is an international reference for Quaternary palaeoclimate and vegetation studies, its peat recording 135,000 years of climatic fluctuations. Since October 2022 the "balade à 1000 temps" trail has carried new interpretive panels and reading tables shaped as gears, pocket watches, a sundial and a chronological frieze.

A waymarked trail with interpretation panels lets visitors walk the site; a new layout, the "Balade à 1000 temps", was installed in October 2022 by the Conservatoire d'espaces naturels de Franche-Comté. Its panels and reading tables take the forms of gears, pocket watches, a sundial and a chronological frieze. The reserve lies at about 330 m altitude in the commune of Saint-Germain, within the Mille étangs area at the foot of the Vosges saônoises.

The reserve is one of Haute-Saône's richest sites for dragonflies, with species of regional priority such as the yellow-spotted whiteface (Leucorrhinia pectoralis), protected nationally and in Europe, and the northern emerald. The viviparous lizard and the common frog also live here, both on the red list of threatened species.