In the book Frankenstein, where was the monster last seen?

The creature eventually introduces himself to the family's blind father, who treats him with kindness. When the rest of the family returns, they drive him away. Hopeful but bewildered, the creature rescues a peasant girl from a river, but is shot in the shoulder by a man who claims her. He swears revenge on Frankenstein for abandoning him to such intolerance, and accordingly kills Victor's younger brother William. When Frankenstein retreats to the mountains, the monster approaches him at the summit and pleads for a female equivalent to mitigate his loneliness. Frankenstein agrees, but, aghast at the possibility of creating a race of monsters, abandons the agreement. In response, the creature kills Frankenstein's best friend, and later kills Frankenstein's bride; whereupon Frankenstein's father dies of grief. Searching for the creature in the Arctic Circle, the scientist falls into the freezing water, contracting severe pneumonia. A ship exploring the region encounters the dying Victor, who relates his story to the captain. Later, the creature boards the ship; but, upon finding his creator dead, is full of grief and pledges to incinerate himself at "the Northernmost extremity of the globe". He then departs, apparently never to be seen again.