The Fed's main interest rate has been practically zero since the dark days of the financial crisis. It has been unchanged since December 2008, a few weeks after the collapse of the investment bank Lehman Brothers.
I say "practically" because the Fed has a target range, of zero to 0.25%, for an overnight interest rate that banks charge for lending to each other.
It is an unprecedented situation and one the Fed's policymakers want to bring to an end, just as soon as they are satisfied that the country's economy is strong enough.