The Carolina Reaper that is grown in Rock Hill, South Carolina, is the hottest pepper in the world according to the Guinness Book of World Records, as of 2014. The pepper measured 1,569,300 Scoville Heat Units according to tests performed at Winthrop University, however, some peppers claim to be hotter.
According to The Chile Pepper Institute at New Mexico State University the Trinidad Moruga Scorpion tested at over 2 million Scoville Heat Units and is the hottest pepper on the planet. The Trinidad Moruga Scorpion is grown on the Caribbean island of Trinidad, but its test results have not been confirmed by Guinness. The island nation is known for its hot peppers with a previous world record holder the Trinidad Scorpion Butch T that requires chemical masks and body suits to harvest.