An Póna aka The Pound, on the Elphin road at Croghan, is a well-preserved piece of local history. It appears on the first Ordnance survey map in 1837 and is as old as the village itself.
Nearly every village once had its pound for stray cattle, pigs, geese etc. to be driven into and there kept at the expense of the owner, till such time as he should pay the fine (the amount claimed by the person on whose land they had strayed, for damage done), and the fee to the pound keeper for feeding and watering the same.
If not claimed in three weeks, the animals were driven to the nearest market and sold, the proceeds going to the impounder and pound-keeper. An ingenious form of receipt was sometimes used. The person who found the animals on his land cut a stick and made notches, one for every beast, and then split the stick down the centre of the notches so that half each notch appeared on each stick; one half he kept, the other he gave to the pound-keeper.
When the owner came to redeem his property and had paid for the damage done, the impounder gave him his half stick. He took this to the pound-keeper, and if the two pieces tallied, it proved he had paid and his beast was freed. Hence the word tally-stick and the pound-keeper being referred to as the tallyman".
If your Croghan ancestor was fined at Croghan Petty Sessions (FindMyPast has records for 1851, 1858-1913) for having animals "wandering on the road", it is very likely they came to this Pound to reclaim them.