The largest previous corporate criminal penalty assessed by the U.S. Justice Department was a $1.2 billion fine imposed on drug maker Pfizer in 2009.
Greenpeace blasted the settlement as a slap on the wrist.
"This fine amounts to a rounding error for a corporation the size of BP," the environmental group said.
Nick McGregor, an oil analyst at Redmayne-Bentley Stockbrokers, said the settlement would be seen as "an expensive positive."
"This scale of bill is unpleasant," he said. "But "the worst-case scenario for BP would be an Exxon Valdez-style decade of litigation. I think that is the outcome they are trying to avoid."
The Deepwater Horizon rig, 50 miles off the Louisiana coast, sank after an April 20, 2010, explosion that was later blamed by investigators on time-saving, cost-cutting decisions by BP and its drilling partners in cementing the well shaft.
The well on the sea floor spewed an estimated 172 million gallons of crude in the Gulf, fouling marshes and beaches, killing wildlife and shutting vast areas to commercial fishing.
After several failed attempts that introduced the American public to such industry terms as "top kill" and "junk shot," BP finally capped the well on July 15, 2010, halting the flow of oil after more than 85 days and putting an end to one of the most closely watched spectacles on TV and the Internet: the live spill-camera image of the gushing crude.
Nelda Winslette's grandson Adam Weise of Yorktown, Texas, was killed in the blast. She said somebody needs to be held accountable.
"It just bothers me so bad when I see the commercials on TV and they brag about how the Gulf is back, but they never say anything about the 11 lives that were lost. They want us to forget about it, but they don't know what they've done to the families that lost someone," she said.