But it will miss us by 745,000 miles (1.2 million kilometers), about three times the distance between Earth and the moon. Still, that is close for such a large rock.
NASA scientists say asteroid 2004 BL86 will come closest on Monday at 16:20 GMT (1:20 a.m. Tuesday JST). That will be the nearest the asteroid gets for another 200 years.
And it will be the closest known encounter by such a giant space rock until another mega-asteroid flies by in 2027.
Amateur astronomers across North America should be able to see it with telescopes and binoculars.