John N. Ahl, Appelant, v. Roswell B. Johnson was a case heard by the United States Supreme Court in 1857 that dealt with the issue of whether or not an individual had to pay for damages caused by their livestock running at large on another person’s property and causing damage to it. The appellant argued that he should not be held liable because his cattle were driven onto the land without his knowledge or consent and thus he could not have prevented them from doing so even if he had been aware of their presence thereon. On appeal, however, the court ruled against him and found him responsible for any damages caused by his animals as they ran at large on someone else's property regardless of whether or not he knew about it beforehand; this decision established a precedent which has since been followed in similar cases involving liability for animal-related damage done to another party's land or goods.

In the case of John N. Ahl v. Roswell B. Johnson, the Supreme Court was asked to decide whether a party who had been wrongfully evicted from their land could recover damages for loss of use and enjoyment during the period they were unlawfully removed from it. The majority opinion held that such damages were not recoverable in this instance because there was no proof that any actual damage had occurred as a result of being wrongfully evicted; however, Justice McLean dissented on this point and argued that even if no physical injury or destruction occurred due to eviction, it should still be possible for an individual to receive compensation for lost use and enjoyment while they are denied access to their property rights by another person's wrongful act. He further noted that allowing recovery would serve as an incentive against future violations since those responsible would have more reason to avoid them knowing they may face financial repercussions if caught doing so.