It was the caravan traders who started that. The Sole Survivor: "The Slog? How'd you come up with that name?"
Even more unique, the settlement is run entirely by ghouls, who formed it after Mayor McDonough exiled them from Diamond City. The name "The Slog" only came about recently after a heavy rainstorm and a trader had to "slog" through all the mud to get a shipment of tarberries, but it was worth it. Once the Middlesex Country public swimming pool, The Slog is the best (and only) tarberry bog in the Commonwealth.