Audubon made some excursions out West where he hoped to record Western species he had missed, but his health began to fail. In 1848, he manifested signs of senility, his "noble mind in ruins." He died at his family home on January 27, 1851. Audubon was buried at the Trinity Churchyard Cemetery and Mausoleum at 155th Street and Broadway in Manhattan. There is an imposing monument in his honor at the cemetery.
Audubon's final work was on mammals, the Viviparous Quadrupeds of North America, prepared in collaboration with his good friend Rev. John Bachman of Charleston, South Carolina. Bachman supplied much of the scientific text. The work was completed by Audubon's sons and son-in-law and published posthumously. His son John did most of the drawings.