<p>Area deprivation is a key contextual determinant of health, yet the consistency of effects on ageing processes over the adult life span remains insufficiently investigated. This study investigated associations between area deprivation and different ageing measures across the entire adult age span in Great Britain. We used data from the UK Household Longitudinal Study. A total of 13,174 participants in Health Assessment (2010–2012) and a DNA methylation subsample of 3,636 participants were included for cross-sectional analyses, as well as repeated measures of subjective functioning from subsequent 13-year follow-up for longitudinal analyses. Area deprivation was measured using the quintile of the Index of Multiple Deprivation, Townsend index, and Carstairs index. Ageing measures included DunedinPACE DNA methylation algorithm, Biological Health Score, cognitive function, and self-reported physical and general health. Linear regression models were used for cross-sectional analyses, and growth curve models were applied to examine longitudinal associations in subjective functioning. Subgroup analyses explored effect modification by individual-level sociodemographic characteristics. Higher area deprivation was associated with accelerated biological ageing, poorer cognitive performance, and worse subjective health, with clear and consistent social gradients across all deprivation measures. Longitudinally, individuals living in more deprived areas experienced persistently worse trajectories of physical and general health over time. Subgroup analyses suggest that area-level associations operate broadly across population groups, with few exceptions. These findings suggest that area-level socioeconomic disadvantage is a consistent contextual correlate of unequal ageing across adulthood that is associated with both baseline differences and, for some outcomes, divergent health trajectories over time.</p>