“…The industrialization of the U.S. economy in the second half of the 19th century brought about a divergence in regional specialization. In manufacturing, regions became highly specialized and by the turn of the 20th century, most of manufacturing employment was concentrated in the regions of New England, Middle Atlantic and East North Central, later labelled the 'Manufacturing Belt' (Fritz, 1943;Perloff et al, 1960;Meyer, 1983Meyer, , 1989Kim and Margo, 2004;Holmes and Stevens, 2004;Klein and Crafts, 2012). This pattern was sustained until the 1940s, after which the degree of regional specialization declined (Kim, 1995).…”