Greenland and Antarctica are the only two locations. 576,000 Square Miles at one mile thick is an area measuring around 800miles by 720 miles. Greenland is larger than that, and Antarctica is larger still. While the ice is often stated to be a mile thick in both places, it is a mile thick at most. In most places, the ice is much shallower, with mountains rising above the level of the ice in both places. When in the past ALL the ice has melted from both land masses, the oceans were about 30 feet higher than they are today. That's the highest it can go. We are already living in a world where most of the ice has melted, and we have been for the last 12,000 years. For comparison purposes, the highest natural point in Florida is 30 feet ASL