Do leprechauns live underground?
If you consider leprechauns to be of the Sidhe (“fairies”) and not little men in green coats with plastic Shamrocks, then yes. In Irish folklore, the Sidhe are the Tuatha De, who retreated into the ground after the Fir Bolg took over in Ireland. They are thought to be living in old ringforts, which possess large underground passages called souterrains.