A series of density models illustrating the gross form of Bouguer anomalies developed during continental collision is compared to Bouguer profiles observed across the Western Carpathians. Gravity models and maps of crustal thickness in Central Europe show that the Moho deepens southward from the European platform to the Outer Carpathians, then rises by more than 10 km across the mountains to the Pannonian Basin. Comparing this overall geometry and Bouguer profiles to the hypothetical models suggests that Tertiary convergence in the Western Carpathians stopped just after ocean basin closure. By this interpretation, the zone of thicker crust beneath the foreland is a geometric consequence of underthrusting the continental edge beneath thick flysch deposit, while crustal thinning to the south may have two components: 1 — original thinning preserved from the Mesozoic continental edge of Europe; and 2 — additional thinning during Neogene opening of the Pannonian Basin. Preserved Mesozoic crustal thinning in the Carpathians would suggest that only a moderate degree of continental underthrusting has occurred, so that the gross form of the continent to ocean transition zone may be intact beneath the mountains.