The last two decades of the eighteenth century saw the emergence of numerous French travel compilations and descriptive texts studying the customs and ways of life of the peasants, an ethnographical interest that developed even further during the First French Republic. In this study, I identify and study a specific genre that I call republican ethnography. The republican ethnography was part of the Enlightenment’s search for a science of society and to the quest of finding the roots of the Republic. Studying travel literature and administrative reports from two French regions, Bretagne and Auvergne, this study examines the character and the meaning of the republican ethnographical projects. The republican travellers and administrators in Bretagne and Auvergne drew on a complex array of knowledge traditions, using categories from climate theory and medical thinking as well as the vocabulary of the travel literature. The study shows that the republican ethnography worked as way of establishing difference, where the French peasant was described as rude and “savage”, as well as similarity, since the travellers and administrators set out to find the unifying principles on which the Republic could be based.