The interaction between man and his environment, which is the basic principle of the science of Geography, is well-illustrated in a study of house-types in Wales. A detailed survey of Welsh house-types is being carried out by the Department of Folk Culture of the National Museum of Wales. It is felt that a study of the traditional types will not only throw much light on the history of culture but will also clarify some issues in the anthropological and archaeological field. This paper may be considered as a brief interim report of part of the survey, supplemented by some material already recorded.