Historical GIS Project that includes a web mapping application and data download features. Interestingly has colour copies of Fire Insurance Plans (Sanborn).
Beyond Steel: An Archive of Lehigh Valley Industry and Culture - GIS - GIS
Comment: no where did I see a mention in the web pages where Lehigh Valley is. There references to Bethlehem and Bethlehem Steel but no specifics of where this is. Lehigh Valley is in Bethlehem, Pennsylvania. Even their web mapping feature has no mention of the geographic area one is viewing.