Argleton is something that some people thought was a town in England, but it turns out it doesn't really exist! It's like a pretend place that some people made up and then lots of people believed it was real. Imagine if someone told you there was a magical land where all the animals could talk, and you believed them even though you had never actually been there and couldn't find it on a map. That's kind of like what happened with Argleton. People saw it written on maps and thought it was real, but really it was just made up.