This dissertation contains three chapters covering the impact of behavioral, socioeconomic, and geographic determinants of health and mortality in high-income populations, with particular emphasis on the abnormally high mortality in Scotland, and the relative advantages of indirect and direct analyses in estimating national mortality. Chapter one identifies behavioral risk factors underlying mortality variation across small-areas in Great Britain, using the indirect estimation method of factor analysis on aggregate cause-of-death information from 1981-2009. Chapter two uses two indirect analytic methods to estimate the contribution of smoking to Scotland’s high mortality and low sex differences in life expectancy relative to other high-income populations from 1951-2009. Chapter three performs survival analysis on first and second generation migrants using a national longitudinal study in England and Wales from 1971-2013 to quantify mortality variation by migrant status and the relative impact of socioeconomic status. The findings highlight the importance of health behaviors on aggregate mortality inequality, support the methodological advantages of indirect estimation of behavioral-attributable mortality, and exposes the importance of subgroup variation within national mortality estimates.