HMS Newcastle was a 50-gun fourth rate of the Royal Navy which saw service in the Napoleonic Wars and the War of 1812. A new type of warship, a large spar-decked frigate, Newcastle and her near sister HMS Leander were a response to the threat the heavy American spar-decked frigates posed during the War of 1812. Newcastle proved a successful ship and operated in squadrons that chased the American frigates, but ultimately failed to catch them before the war ended. She spent some time as the flagship on the North American Station before returning to Britain in 1822 and being laid up. She was later converted to a lazarette. She spent the rest of her career in this role, until she was sold in 1850 for breaking up.