The Midwest was one of the few regions in the country, where the interurban railway networks were well developed. Good networks radiated out of Detroit, Indianapolis, Milwaukee, and existed in various parts of Ohio. But even then, there were significant gaps in the interurban networks. For example, Chicago did not connect with downstate Illinois, downstate Indiana, or most of Michigan. And the interurbans reaching Green Bay were isolated from the interurbans from Milwaukee. And interurbans never reached Madison, Wisconsin.
But beyond the Midwest, the interurban networks were even more fragmented, except in the densely populated Northeast. Although many of the railways there did not completely meet the "interurban" definition, because of little rural land between many of the cities served.
Years of operation include years when any portion of the route was operated, except for local streetcar segments. Some lines were constructed or abandoned in segments. Non-electric operation is not included.
Not listed are what the book authors have sometimes labeled as "rural trolley lines". Although the authors admit that the distinction from interurban railways is not always clear. Many of these other electric railways were in the more densely populated northeastern United States. And those state or regional pages linked to from above, include links to maps which show these extensive networks of electric railways. Most of these electric railway lines, and their bus replacements, were basically extensions of the local transit systems, which are covered in the "Transit Present And Past" section of this Web site.
Also included, where available and practical, is information on bus services which eventually replaced the interurban railways. Many of the interurban bus lines eventually became part of Greyhound and other intercity bus systems, unfortunately to be mostly discontinued after the deregulation of the 1980's. While a few interurban lines of a more suburban nature eventually became parts of local transit systems, which continue to operate the bus lines. The Greyhound and other intercity bus systems are covered in the "Interurban And Intercity Buses" section of this Web site.