John Hart's eldest son , Jesse, left the Hopewell NJ area after his father's death. He was in Washington co. Pa by 1790's and in what is now Beaver co, by that same decade. He settled in Crow Bottom and owned/ran a hotel. He died in Crow Bottom ,Beaver co in Jan . 1815. He has 6 children and at least 4 of them left descendants. One son, John, died in Sewickly. Another died in Pittsburgh(Aaron Hart). There were 3 daughters who married and stayed in the region. So, yes there were signer's children and grandchildren in Allegheny co and Pittsburgh. By the mid 1800s there were John Hart descendants in Beaver, Alleghenny, Mercer and Fayette counties. And probably others in Somerset and Bedford Counties that I should try harder to trace.