Semilly is a small commune in Haute-Marne, in the Grand Est region. Insee counted 94 residents across the whole commune in 2023, a reference figure published in August 2026; the density was 6.4 inhabitants per square kilometre. The distinction between the commune and its central village matters here: this is a very lightly populated rural place, not a town with a busy high street or a large menu of visitor facilities. Its strongest documented landmark is the church of Saint-Martin, whose fabric lets a short visit become an encounter with several centuries of local building history.
Saint-Martin, a church rebuilt in stages
The Haute-Marne visitor heritage record describes a three-bay nave, a south aisle of four bays, a one-bay choir and a five-sided apse. It dates the oldest surviving parts to the thirteenth century, while noting extensive alterations at the end of the fifteenth century. An inscription on the south exterior carries the date 1483. The contrast between older structure and later rebuilding is the most rewarding detail to look for: the church is not a frozen medieval shell but a building reshaped for continued use. A government heritage record confirms its legal protection by inscription on 13 July 1926.
The visitor record also mentions a door secured by a beam. It suggests that the church may have served as a place of refuge during the Thirty Years' War, but that is an interpretation of the hardware, not a proven event in Semilly's history. The distinction is worth preserving. The available local heritage account gives concrete dates and architectural observations; it does not establish a fuller tale of a siege, a founder or a miraculous origin. No legend needs to be invented to make the building interesting.
A small rural economy, read with care
Insee's 2024 business register counted seven economically active legal units in its non-agricultural market-producing scope: three in real estate, two in manufacturing or related industry, one in construction and one in other services. It counted eight establishments in the same broad scope, including one in commerce, transport, accommodation or food service. These numbers are small and their definition is narrow: they exclude agriculture and public-sector activity, and they do not describe every resident's job. They are best used as a modest snapshot, not as a complete account of village livelihoods.
Semilly belongs to the Communauté de communes Meuse Rognon, and Insee dates the current commune record to 1 January 1997. For practical needs, the official government directory lists the mairie at 2 rue de la Croisette, with telephone and email contacts. It displays reception hours on Tuesday afternoon and Thursday morning to early afternoon, but that listing was last modified in 2024; check before making a special trip. The same directory identifies France Services in Andelot-Blancheville, 11.6 kilometres away, for administrative help beyond the services available in the village.
Walking in the surrounding basin
No current marked walking loop starting in Semilly was confirmed in the sources consulted. A documented nearby option is Les 4 Vierges, a circuit whose trailhead is in neighbouring Saint-Blin. The Haute-Marne attractiveness agency lists it as an 18-kilometre difficult route, about four and a half hours on foot, with 380 metres of positive elevation. Its loop connects four communes in the Manoise basin and uses forest tracks and ridge paths. It is an area outing rather than a Semilly village walk, and the route listing's safety notice makes checking current signs, access and ground conditions sensible. Visitors who want only to see the church can plan a shorter stop without treating the regional circuit as a necessary part of the visit.
Semilly rewards a measured pace: arrive for the church's medieval and late-medieval details, allow time for the surrounding rural setting, and use the mairie or the local tourism service to confirm what is open. Do not assume that the church is unlocked or that walking routes are maintained on a particular day. The sources establish a protected monument and a nearby route, while current access remains something to verify locally.
