Known migration in The Netherlands between the periods 1950– 1969 and 2007, for 4.5 million individuals, was used to estimate the origin of migration by means of a Bayesian method on the basis of surname distributions in these two periods. Results of the method depend on the geographic specificity of the surnames and tend to be positioned between population density and actual probability of migration origin. An optimum in the correlation between estimated and actual percentages of origin of migration, and their differentiation as expressed by the correlation between the estimated and actual entropy across 40 distinguished areas, was found after a few iterations. The optimal correlation was 0.806 (Spearman), which shows that the Bayesian method provides a reasonable proxy of the rank order of a migrant's origin.