He continued to publish regularly throughout his life, and he completed a five-volume biography of George Washington just eight months before his death at age 76 in Tarrytown, New York.
Ia terus menerbitkan karya secara rutin—dan hampir selalu sukses—sepanjang hidupnya, dan menyelesaikan biografi George Washington sebanyak lima volume delapan bulan sebelum kematiannya pada usia 76 tahun di Tarrytown, New York.