Risk of Hodgkin's disease (HD) in young adults has frequently been associated with limited access to social contact in childhood and related correlates of childhood social class. In addition, case clustering has sometimes been associated with influxes of population into relatively isolated communities. To investigate this further, disease incidence rates for HD at ages 0 to 24 from a specialist tumour registry have been regressed against relevant electoral ward characteristics derived from routine census and Ordnance Survey data for England and Wales. Proximity to built-up areas and higher socio-economic status (SES) emerge as significant risk factors. The relative risks are 1.21 (95% Cl: 1.01-1.46) for high SES wards and 1.29 (1.05-1.58) for "inner zone" wards. No association of disease risk with distance travelled to work was apparent. Regions farther from built-up areas have a lower overall incidence and a shift, particularly for males, of the age distribution towards older ages. The distribution resembles the intermediate pattern for HD reported from European rural areas of low SES but never previously for high SES. Isolated areas also show an increased intensity of spatial clustering (29% of cases being classified as clustered). These findings have implications for the 'late host response' model which suggest a viral aetiology for Hodgkin's disease in young people and provide a basis for future analytical studies.