As highlighed by Perroux economic growth does not appear everywhere at once and at the same rate, but it emerges from certain growth poles and diffuses from there. Hence, agglomeration and economic growth are related phenomena. Following Perroux, this thesis investigates Swiss economic growth as a spatial phenomenon. It argues that agglomeration economies have significantly contributed to Switzerland's most important growth phase between 1850 and 1910, whereas the limits imposed on spatial economic concentration during the second half of the 20th century have aggravated Switzerland's growth slack after 1970. This thesis is not only a case study in historical economic geography, but by resolving a serious measurement problem of Swiss GDP and elaborating an extraordinarily detailed geographical dataset it lays the foundation for many future studies on economic growth and regional development in Switzerland. It is one of the first studies to adress the relation between agglomeration and economic growth.