The Jamestown settlement impacted the United States in a number of ways, both good and bad.
On the good side, Jamestown was an economic driver of early Virginia. The discovery that tobacco could be a viable economc crop was made at Jamestown very early in the settlement's history. The tobacco trade contributed greatly to the wealth of the colonies and, by extension, the early United States.
On the negative side, Jamestown "contributed" to problems between white colonists and non-whites, problems which continue to haunt us today. The Jamestown settlement and its eventual expansion helped lead to very poor relations with the Indians. Eventually, this took the form of attempts to kill or drive out the Indian population. Furthermore, the Jamestown tobacco industry helped to bring about the slave system in what would become the United States. This helped, of course, to lead to the Civil War and to the issues of race that continue to be problematic for the US today.
In these ways, Jamestown contriubted in important ways, both good and bad, to what would become the United States