The largest officially recognized hailstone on record to have been "captured" in the U.S. was that which fell near Vivian, South Dakota in 2010. It measured 8.0 inches in diameter, 18.5 inches in circumference, and weighed in at 1.9375 pounds. Mr. Lee Scott, who collected the monster stone, originally planned to make daiquiris out of the hailstone but fortunately thought better and placed it in a freezer before turning it over to the National Weather Service for certification.
More on record-setting hail from our Weather Historian, Christopher C. Burt.
The largest hail stone on record in the U.S. was an eight-inch monster that fell on July 23, 2010 in Vivian, South Dakota.