what is the name of the major city were two major rivers intersect that is centrally located in the US

if you mean the word; its confluence

Explanation:

In geography, a confluence (also: conflux) occurs where two or more flowing bodies of water join together to form a single channel. [1] A confluence can occur in several configurations: at the point where a tributary joins a larger river (main stem); or where two streams meet to become the source of a river of a new name (such as the confluence of the Monongahela and Allegheny rivers at Pittsburgh, forming the Ohio); or where two separated channels of a river (forming a river island) rejoin at the downstream end.

the density would be a smaller number.