Why was the capital of the US moved from New York?

The south wanted some concessions on getting the capital moved to more middle ground like potomac. So A deal was made- to move the capital if Alexander Hamiltons bank was to be approved; and paying off the war debt with bonds was to go ahead as planned. Politics

Answer

Simply, to make the South happy. The South felt that if the Capital of the U.S. was all the way up north in New York, the the South would be ignored. So as a way to keep the South part of the U.S., it was agreed upon to move it further down.