This paper develops an area classification to examine immigration, ethnic diversity, and its social consequences in local authorities of England and Wales. Using a set of demographic, socio-economic and migration variables drawn from survey and administrative data and cluster analysis methods it produces a twelve-fold classification of local authorities. The classification includes groups of traditional immigrant settlement areas with high flows of migrants of different migration streams and nationalities, smaller urban and semi-rural areas with high migration rates associated with a dominant migrant group, as well as areas with migration rates close to the national average or below average migration rates. By taking into account the nuances of diversity and immigration and the local socio-economic context in which migrants settle, the classification provides a useful framework towards understanding the different ways immigration can impact on social cohesion and how local policies can be more responsive to the needs of local populations. Examination of attitudes to immigration, perceptions of cohesion and social mixing suggest that less ethnically diverse local authorities with a dominant migrant group and socio-economically deprived local authorities are most at risk of experiencing higher pressures on social cohesion.