We studied the isonymic structure of Western Europe using the distributions of 26.2 million surnames in 8 countries, 125 regions and 2094 towns of the Subcontinent. We found that, for the whole of Western Europe, Nei's distance was correlated with geographic distance (r=0.610+/-0.009). It was observed that at long geographic distances the isonymyc distance stays below linearity and tends to become asymptotic, and this was attributed to long distance migration. A dendrogram of the125 regions was built and the clusters identified by the dendrogram are almost exactly coincident with the nations of the Subcontinent. Random inbreeding calculated from isonymy, F(ST), was highest in Spanish regions, and lowest in France. The geographical distribution of alpha in 2094 towns, high in the Center and East of the Subcontinent and lower in Spain, is compatible with the settlement of subsequent waves of migrants moving from the West and from the South toward the centre of the Continent. The present surname structure of Western Europe is strictly linked to local languages.