"Contrary to a widespread misconception, the 56 signers did not sign as a group and did not do so on July 4, 1776. The official event occurred on August 2, 1776, when 50 men probably took part. Later that year, five more apparently signed separately and one added his name in a subsequent year. Not until January 18, 1777, in the wake of Washington's victories at Trenton and Princeton, did Congress, which had sought to protect the signers from British retaliation for as long as possible, authorize printing of the Declaration with all their names listed. At this time, Thomas McKean had not yet penned his name.
"The most impressive signature is that of John Hancock, President of Congress, centered over the others. According to tradition, Hancock wrote boldly and defiantly so that King George III would not need spectacles to identify him as a 'traitor' and double the reward for his head. The other Delegates signed in six columns, which ran from right to left. They utilized the standard congressional voting order, by colony generally from north to south: New Hampshire, Massachusetts, Rhode Island, Connecticut, New York, New Jersey, Pennsylvania, Delaware, Maryland, Virginia, North Carolina, South Carolina, and Georgia.
"Those who signed on August 2 undoubtedly did not realize that others would follow them and thus allowed no room to accommodate the signatures of the later six men. Two of them, George Wythe and Richard Henry Lee, found ample room above their fellow Virginians. One, Elbridge Gerry of Massachusetts, crowded his name into the space between the Massachusetts and Rhode Island groups. Two of the others--Thomas McKean and Oliver Wolcott--signed at the bottom of columns following their State delegations. Only Matthew Thornton of New Hampshire needed to add his name separately from his colleagues--at the bottom of the first column on the right at the end of the Connecticut group."
--from the book Men of Freedom: Profiles of the Signers of the Declaration of Independence (Pathmaker Books, 1975), pp. 23-24 (Note: In addition to biographical sketches of all fifty-six of the signers, this wonderful old book includes the historical background of the Declaration of Independence and tells what happened to the original document of the Declaration in the two hundred years following its publication. Unfortunately, this treasure has been out of print for many years and is now very difficult, if not impossible, to find.)