The electromagnet weighs at least 15 tons and was the largest in the world when it was built by scientists at Brookhaven National Laboratory in the 1990s.
Brookhaven scientists no longer have a need for the electromagnet, so it is being moved to the Fermi laboratory, where it will be used in a new experiment called Muon g-2.
The results could create new discoveries in the realm of particle physics.
The magnet will be taken by barge down the Atlantic, around Florida, then up the Mississippi River to Illinois.
The move is expected to cost about $3 million.
But constructing an entirely new electromagnet could cost as much as $30 million.