The difficulty in discovering what port an ancestor used is that not everyone used a conventional port or harbor to enter America. The quantity of how many immigrants clamored over the side of an anchored vessel  to waiting row boats will never be revealed. Certainly, the use of row boats and rafts to get from the ship to the shore would have been the means in which the earliest settlers had used to set foot on shore. It took time to discover rivers and natural harbors that were deep enough to except the draft of the first sailing ships. The Mayflower, with it’s 180 ton capacity and little over 100 passengers was designed for the mouth of the Hudson River, though it ended up at Plymouth Rock.
     Establishing docks and piers would have been  slow to appear, and their use and locations would have been eventually disseminated to the next wave of ships. Cargo, whether it be settlers, slaves, or commodities, would flow through the common areas where the geography and topography would permit it.  Some rivers could not be entered until the sea level rose enough to allow ships to enter the inland waterways. For settlers and immigrants, it was not anything like Ellis Island, and no one took names as they tramped through the cold surf to begin their lives in the New World. Below is a brief description and history of the major early ports in America:
      Boston Harbor: is a natural harbor, protected from the Atlantic by a combination of the Winthrop peninsula and Deer island to the north.  It is often referred to as being split into an inner and outer harbor.   The harbor area was first attempted to be settled in 1623 by an expedition which originally sailed to New England. It failed but, Rev. William Blackstone remained behind in what is today known as Boston’s Beacon Hill. Three years later the Puritans, fleeing from English persecution, came to the area. By the 1760’s the city swelled in size and the citizens grew  increasingly antipathetic to the Britons whom decided to tax the British colonies, eventually leading to the Boston Tea party in 1773.
   New York Harbor: includes the Upper and Lower New York Bay, the North river, part of the Hudson river, and several other Bays, Kills and the Harlem river. At the harbor’s peek, some 11 individual active ports resided in New York city, New Jersey and Staten island. It has been agreed that the first recorded European in the harbor was Henry Hudson in 1609.  In 1624 the first permanent European settlement was started on Governors island and eight years later in Brooklyn. The colonial Dutch ordered the first wharf to be built and it was completed in 1648. In 1686, the control of the leading port for the British was given over to municipality control.
   Philadelphia:  eclipsed Boston and New York in political and social importance and population in the 1700’s. In 1669 Swedish colonists became the first Europeans to settle the area. William Penn the renowned Quaker, who founded and developed Philadelphia in 1682 had encouraged thousands of Quakers to gobbled up land both in the city and inland.  In 1790 the US government was moved to Philadelphia and was the temporary capital of the nation until 1800.
   To reach this city, ships traveled through Delaware Bay and up the Delaware river. Because the tidewater reaches pass Philadelphia and meets the river at Trenton, New Jersey, commerce was very important on the upper river until railway competition in 1857.  However the average tide of six feet was obtained below Philadelphia causing improvements to be made to the river’s navigation as early as 1771. 
   Baltimore harbor: was reached by traveling up the Chesapeake Bay to a natural deep water harbor which began trading in 1706.  Fort McHenry was used as the first port of entry for the area’s tobacco trade with England. Baltimore Town which was later to become the city of Baltimore was established  in 1730. Fells point, the deepest part of the harbor evolved into a leading colonial ship building center which became famous for it’s sleek and maneuverable Clipper ships. The city had only twenty five buildings by 1752, but soon after that began to grow rapidly when the economy switched from tobacco to flour mills to feed expanding Pennsylvania population. The area had a diverse group of inhabitants whom were attracted to the area. By1756 settlers included, Arcadians, French speaking Catholics from Nova Scotia, Germans, Irish and Scottish nationalities.  Around 1806 Baltimore became a gateway for settlers headed for the Ohio Valley and other favorite destinations to settle.   
   James River: of Virginia was named after King James I. of England. It was the site of the first earliest English settlement in 1607 at Jamestown which failed.  The first ships crossed  the Chesapeake bay and traveled up the river’s mouth at Hampton Roads. As tobacco grew as an important crop, plantations with wharfs along the river’s banks sprang up, stimulating more immigration for the first 75 years in the Tidewater regions. Ocean going ships could not navigate past present day Richmond and Manchester, thus stimulating port towns like Lynchburg, Scottsville, Columbia and Buchanan to send product down river by small boats.  Eventually English and Welsh immigrants continued to press inward through out Virginia and North Carolina and further west.
   Charleston harbor: South Carolina has three major rivers flowing into it; Ashley, Wando and Cooper. The area was first settled by the English in 1670.  They settled on the Ashley river and later moved to Oyster Point, the present site of Charleston.  It was first called Charles Town after King Charles II of England. The first settlers were from England and the Caribbean islands, followed by Huguenots, Quakers, Scottish, Irish and Belgian.  Because the port was considered one of the most religiously tolerant of the colonies, it attracted settlers of different faiths. By 1700 over 5,000 lived in the area. Part of the colorful history of the port was the trade with England of corn, pork, lumber, deerskin and rice which was threatened by pirates demanding ransom. Today only Fort Sumter remains of the earlier fortification to protect the city. During the revolutionary war the city was divided and endured much strife, followed by turmoil over slavery until the end of the civil war.
   Georgia and Florida ports were conspicuously absent from the compiled lists of immigrants. This was mostly due to the fact that the navigable ports like, Savannah Georgia, Biscayne and Tampa Bay of Florida were under early Spanish control. These two most southern states, during the 16th and 17th century, as well as the gulf states were used as pawns for the chess match between the Spanish and French whom were most of the time either an enemy or at least in competition with England. Savannah was not established until 1733 and  Florida wasn’t an organized territory of the United states until 1822, two years after U.S. decided to keep records of immigrants.      
  Mobile Bay: was first visited in 1519 by a Spanish explorer. The area was briefly settled in 1559 before re-settling to Pensacola Bay, and it was not until the late 1600’s before it was used by the French whom laid claim to the mouth of the Mississippi river. Facilities on Mobile Bay’s Dauphin island, which was a deep water harbor, became the French’s attempt to halt both Spanish and English sprawl of the gulf.  By 1701 the island became the first capital of the growing French colony of Louisiana. The city of Mobile evolved from the French settlement in 1711. The area was held until the Treaty of Paris in 1763 which ceded the Louisiana territory to England, only to have Mobile taken from the English by Spain in 1780. Alabama finally becomes a territory of the U.S. in 1817, separating from the Mississippi territory and becoming a state one year later.  
    New Orleans: was founded in 1718 by the French. The site was selected because it was a rare bit of natural high ground along the flood-prone banks of the lower Mississippi. It was named after a Regent of France, Phillip II, Duke Orle’ans. In 1722 this site of hovels in a malaria wet thicket of willows was made the capital of French Louisiana. After a hurricane blew most every structure down, an area was built in a grid pattern which is today known as the French Quarter. The city hosted an eclectic group of trappers, prospectors and other referred to as undesirables. In 1763 the colony was secretly ceded to Spanish rule, but that did not last long. The great fire of 1788 destroyed 856 buildings on Good Friday.  The sugar industry, and the expanding use of the Mississippi river for  transportation in the last twenty years of the 18th century, increased the stature of the city.  In 1803 Napoleon sold Louisianan to the United states. By 1820 New Orleans had over 10,000 people of various mixed nationalities which included the migration of  French planters from Cuba.
   Galveston Bay and Houston ship channel:  occupy the western most area of the Gulf. The area was first visited by Spanish explorers whom met up with a particular fierce tribe of Indians, and was not considered a favorable place to settle in the 16th and 17th century. In the early 1800’s buccaneers had a short lived settlement on Galveston Island. It was not until 1820 before settlers began moving into Texas was Galveston Bay area found to have many rich resources like shellfish, forests, construction materials, and prairies for farming.   Alterations of the bay began with several canals, including the most important being the Houston ship channel in 1836 which linked the City and Port of Houston to the Gulf of Mexico by way of Galveston Bay.  Dredging was conducted in the intercostals waterways in order to enhance shipping and navigation . In 1837 the Republic of Texas emerged from the war with Santa Anna and Houston became briefly the capital. Texas became a state of the United States in  1845. By 1870 the city had 9,000 citizens.   
       The final port listed with an immigration record was on the far west coast at San Francisco  Harbor.  San Francisco Bay is a shallow estuary with interconnecting rivers, bays and waterways which drain much of northern California.  The bay was navigable as far south as San Jose until the 1850’s. Massive amounts of sediment from rivers and mining operations, reduced the Bay’s size. The first recorded European to find his way into the bay was in 1775 by a Spanish explorer. San Francisco became the premier location for settlers moving westward after 1820.  After the seizure of the region from Mexico, California was annexed to the U.S and became a state in 1846. The gold rush of 1849 assisted a migration to California by both land and sea routes. It was not an important port until the railroad reached the bay in 1869, urging the creation of additional wharfs in Oakland and other areas.
   The above data gives the researcher a general time line of the events surrounding the major ports. I hope this gives a better understanding of what family ancestors may have confronted during certain periods of time in US history.