1. United States Overview North America

2. United States of America 38.8833° N, 77.0167° W

3. United States of America The United States of America (USA)—commonly referred to as the United States (U.S.), America, USA— is a federal republic consisting of 50 states and a federal district. The 48 contiguous states and Washington, D.C., are in central North America between Canada and Mexico. The state of Alaska is located in the northwestern part of North America and the state of Hawaii is an archipelago in the mid- Pacific.

4. Timeline Sale- Wagon Epoch (1790-1830) Marked by primitive overland and water way circulation Leading cities were Boston, New York and Philadelphia Heavily oriented to the European overseas trade Erie Canal- links the coast and the Great Lakes

5. Iron Horse Epoch (1830-1870) Dominated by the arrival and spread of the steam powered railroad 1869- transcontinental line was opened Nation wide transport system has been forged and coal mining centers boomed. 1850- New York became primate state Pittsburgh, Detroit and Chicago became the industrial cities

6. Steel-Rail Epoch (1870-1920) Spanned the US Industrial Revolution Several forces shaping the growth and development of the metropolitan system: - rise of pivotal steel industry along the Chicago-Detroit- Pittsburgh axis -the increasing scale of manufacturing that necessitated the agglomeration in the most favored raw material and market locations for industry -the use of steel in railway construction

7. Auto-Air-Amenity Epoch (1920-1970) Encompassed the later stage of the US industrial urbanization and the maturation of the national urban heirarchy The key innovation was the gasoline powered internal combustion engine Technological advances in manufacturing led to the increasing automation of blue-collar jobs

8. Satellite- Electronic- Jet Propulsion Epoch (1970- ) Shaped the newest advancements in global scale communications, computer technologies and transoceanic level as transportation breakthroughs permitted progressive urban decentralization and megalopolitan growth, the expanding peripheries of major cities soon coalesced to form a number of conurbations Atlantic Seaboard Megalopolis- 600-mile urbanized northeaster coastal strip extending from southern Maine to Virginia that contains megalopolis Boston, New York, Philadelphia, Baltimore, and Washington. This was the economic heartland of the US core region