Today we know it as the Delaware River, which forms the boundary between the states of Delaware, New Jersey and Pennsylvania. To the Dutch it was the South River, since it was the main highway through the southern part of New Netherland (by the same logic, they called the Hudson River the North River). It was a vital part of the colony, which would leave a fascinating collection of legacies in American history and culture. The cities of Wilmington, Trenton and Newark started life as trading centers in this era. The state of Delaware owes its existence to the short-lived Dutch settlement of Swaanendael.

In 1638, this area also became the site of yet another European venture when a Swedish expedition sailed into Delaware Bay and established the short-lived colony of New Sweden at present-day Wilmington (the area of Wilmington waterfront where the ship docked is still called Swedes' Landing). In its seventeen years, New Sweden expanded as far north as present-day Trenton, New Jersey. However, the Dutch of New Netherland were not going to stand for an incursion into their territory, and in 1655 Peter Stuyvesant himself led a military expedition to the Swedish fort on the Delaware, overwhelming the troops there, and bringing New Sweden to an end - just as, nine years later, an English military flotilla would sail to Manhattan and force Stuyvesant to give up New Netherland.