How has geography influenced the settlement of the United States?

Geography plays an important role in any settlement.  In the United States, this is evidenced by the location of many major cities in the nation.
Most early settlers to the United States arrived from European countries.  Settlers came from England, France, Holland, Spain, and other European countries.  They sailed on ships across the Atlantic Ocean and arrived on the East Coast of what is today the United States.  There are many historically important cities on or near the Atlantic Ocean, such as Boston, New York City, Charleston, Savannah, and St. Augustine.  These were the ports of entry for many European immigrants and African slaves.  Other cities were developed along rivers and bays that fed into the Atlantic, such as Hartford, Philadelphia, and Baltimore.  Boats were the most common mode of long distance travel in the 17th, 18th, and early 19th centuries, so it was important to build major cities along the water.  Transport of goods was done primarily by ships and boats.  Most major cities were located along waterways for trading purposes.
Prior to the 19th century, most settlers lived in the Eastern United States.  Westward expansion became a popular idea in the 19th century, and more cities were established further inland.  Popular travel routes, such as the Oregon Trail, encouraged settlers to move west.  They established cities along the way and on the West Coast.  Land parcels beside rivers and lakes were still popular locations for building cities.  Cities were also built along the Pacific Ocean.