GrandTerrier is a cooperative history and heritage website devoted to Ergué-Gabéric, a commune in the Breton region of France. Inspired by the local name Erc'hié-Vrâs, meaning “Grand Ergué,” the site aims to preserve the memory of the area and its people through accessible, community-supported research. Its extensive online collection includes articles on archives, biographies, Breton language and culture, local villages, historic buildings, maps, papermaking, newspapers, and audiovisual materials.

The project also highlights figures connected with the commune, including writer Jean-Marie Déguignet, whose memoirs recount his childhood there. Articles are collaboratively developed, updated, and documented with sources, and their revision history is available to readers. GrandTerrier publishes weekly posts, quarterly bulletins, and illustrated notices, while offering online registration for contributors and readers who wish to receive updates.

The site is designed for computers and mobile devices, with an option to install it as an app. Supported by the association Les Mémoires du GrandTerrier, it serves as a shared local history resource and evolving digital museum