Transportation and the Location of Cities 219 
along every one of the numerous railways that center in the city. 
Except when the Great Lakes are icebound, steamships of at least 
eighteen different companies are speeding to the city with their bur- 
den of goods and passengers from the fertile and well populated hin- 
terland. At the same time, as many more trains and steamships are 
hurrying away from the city to distribute goods and passengers to the 
same great hinterland. 
The most productive part of the hinterland is included in a circle 
with a radius of 425 miles, centering at Chicago. Such a circle con- 
tains about half a million square miles of plains whose productiveness 
is scarcely excelled by that of any similar area in any part of the earth. 
It includes an area as large as Great Britain, France, and Germany 
combined. It also contains most of the Great Lakes, which offer the 
best facilities for inland navigation in any part of the world. 
Chicago illustrates the fact that where the convergence of land 
routes makes it necessary to have a harbor, man can build one even 
without help from nature. At the southern end of Lake Michigan 
there are no good harbors, and Chicago is located merely at the mouth 
of the little Chicago River. Improvements have constantly taken 
place, however, and when the present plans are completed the city 
will have an unsurpassed inland harbor. 
How transportation has helped the growth of Detroit. Although 
Detroit lies on a river, it is essentially a lake port. Among the lake 
ports of the world it comes next to Chicago in size. It is nominally 
the fourth city in the United States, although metropolitan Boston 
and Pittsburgh are both larger than metropolitan Detroit. 
Detroit, like Chicago, lies near the end of a great lake. There a 
railway route between New York and Chicago meets a water route 
connecting the iron mines and the coal mines. Although the rail- 
way route is shorter than the one on the south side of Lake Erie, it is 
less important. This is partly because a portion of it passes through 
foreign (i.e., Canadian) territory, and partly because it passes through 
[ew large cities. The iron-ore route helps Detroit relatively little be- 
cause most of the ore goes past Detroit in order to reach a port as near 
the coal mines as possible. Thus in this case, even more than in others, 
transportation is only one of the factors in the extraordinary growth 
of the city. The fact that the automobile industry centers here is in 
many ways much more important. 
The western end of Lake Erie and the southern end of Lake Huron 
form so important a center of communication that Toledo as well as 
Detroit has grown up here. It lies on the drowned mouth of the