You can use the following sources to determine if you are a descendant of a signer of the Declaration:
Only 15 of the 56 signers have male descendants today.
These Signers have no descendants: William Whipple, John Hancock, Samuel Huntington, James Smith, James Wilson, Caesar Rodney, George Wythe, Francis Lightfoot Lee, Joseph Hewes, Thomas Lynch, Jr. Button Gwinnett, Lyman Hall, and George Walton.
These Signers have no same surname (male) descendants: Josiah Bartlett, Matthew Thornton, Samuel Adams, Elbridge Gerry, William Williams, William Floyd, Francis Lewis, Robert Morris, Benjamin Rush, Benjamin Franklin, George Clymer, George Taylor, George Ross, Thomas McKean, Samuel Chase, Thomas Stone, Thomas Jefferson, William Hooper and John Penn.
These Signers have very doubtful same surname (male) descendants: Stephen Hopkins, William Ellery, Oliver Wolcott, John Witherspoon, Abraham Clark, John Morton, Carter Braxton, Edward Rutledge.
There are several good sources of genealogical data on the Signers descendants. A source document, The Leach Manuscript, may be seen on microfilm at an LDS Family History Library in Salt Lake City, or in more than 3,500 Family History Centers located around the world. For the FHC nearest you, visit Family History Centers.
In addition, there is a seven volume series, The Genealogical Register of the Descendants of the Signers of the Declaration of Independence, by The Rev. Frederick Wallace Pyne. These volumes are arranged by State. Each volume contains detailed genealogical data on the descendants of each signer from that State. The books are available from Picton Press.
Another source is Signers of the Declaration, Index and Images for the Applications to the descendants of the Signers of the Declaration of Independence. This book is published by Willow Bend Books. This book and CD collection contains the index to the material in the FHL mentioned above as well as copies of 2,673 application for membership in the Society.