Why is John thornton camped there?

John Thornton is camped there to pursue gold prospecting in the Yukon Territory during the Klondike Gold Rush. He seeks fortune and adventure in the wilderness, driven by a desire for a better life and the hope of striking it rich. Additionally, he has formed a bond with Buck, who plays a crucial role in his journey and companionship in the harsh environment. This setting reflects themes of survival, loyalty, and the search for purpose.