This paper estimates regional GDP for three different geographical levels in Switzerland. My analysis of regional inequality rests on a heuristic model featuring an initial growth impulse in one or several core regions and subsequent diffusion. As a consequence of the existence of multiple core regions Swiss regional inequality has been comparatively low at higher geographical levels. Spatial diffusion of economic growth has occurred across different parts of the country and within different labor market regions at the same time. This resulted in a bell-shape evolution of regional inequality at the micro regional level and convergence at higher geographical levels. In early and in late stages of the development process, productivity differentials were the main drivers of inequality, whereas economic structure was determinant between 1888 and 1941.