Two major culture provinces can be recognized in modern Wales: Cymru Gymraeg or Welsh Wales in the north and west; and Cymru ddi-Gymraeg or anglicized Wales in the east and south. Adopting Meinig's typologies, Carter and Thomas have proposed a model of a culture region in decline, recognizing Cymru Gymraeg as the 'core' culture area and equating territories within Cymru ddi-Gymraeg with the 'domain' and 'sphere'. At the present time the whole culture complex has reached an advanced stage in the process of decay: the 'domain' has now been virtually eliminated so that the 'core' is under direct assault from alien influences in the 'sphere'. This paper explores the anatomy of the Welsh culture region at an earlier stage in the process when industrial and urban growth was beginning to make a strong impact on the indigenous culture. North-east Wales, a region which experienced a quickening of industrial development during the early nineteenth century, is the region selected for detailed study. The analysis begins with an outline of regional demographic trends between I750 and 1851. Using sample data from the 1851 unpublished census enumerators' books, patterns of lifetime migration and the consequences of the location of language divides and the maintenance of culture areas are examined. The final section deals with the diffusion of distinctive Welsh and English religious denominations into and within north-east Wales, using data from the unpublished schedules of the i851 census of religious worship. The study reveals the existence of a well-defined bilingual zone in the cultural transition between Cymru Gymraeg and Cymru ddi-Gymraeg. This bilingual zone can be equated with the 'domain' of Meinig's culture region model but, in many respects, it also functioned as the 'strategic front' where, in the mid-nineteenth century, the greatest threat to the indigenous culture of the 'core' was concen- trated. IN 1959 Bowen published his classic paper Le Pays de Galles as a corrective to what he considered to be the stereotyped interpretations of generations of writers who had treated the political area of Wales as a homogeneous culture region. Pointing out that the Welsh people themselves recognized numerous 'pays' within their own country, Bowen argued that the cultural heartland of Wales is to be found '. .. in the land of the people who speak the Welsh language', that is, in the predominantly Welsh-speaking communities of the northern and western counties. These distinctive areas constitute the '. . . real Pays de Galles within the framework of the larger national territory'. Moreover, they are now the residual territories to which the indigeneous culture has contracted. As such, Le Pays de Galles is to be clearly differentiated from the peripheral regions to the east and south where the percentages of Welsh speakers progressively fall away.' In effect, therefore, Welshmen recognize two major culture provinces within their own country: Cymru Gymraeg or Welsh Wales in the north and west and Cymru ddi-Gymraeg or anglicized Wales in the east and south.2 The spatial anatomy of these distinctive provinces has been explored by Carter and Thomas. In the adoption of Meinig's typologies they have identified Cymru Gymraeg as the 'core' culture area, the regional component most representative of the indigenous culture at the present time. The 'domain' and 'sphere' of Meinig's model find expres- sion in Cymru ddi-Gymraeg: the 'domain' in territories until recently still dominated by the indigenous culture, but with less intensity and with less homogeneity than in the core; the 'sphere' in outlying areas still farther to the east and south where, for historical reasons, Welshness may be