Detectives from the Kildare Drugs & Crime Unit, assisted by local gardaí, seized cannabis plants and herb with an estimated value of €700,000.
With plants worth an estimated €800 each, the total haul would indicate around 875 plants in all were found.
Any cannabis growhouses with more than 500 plants are considered by gardaí as industrial-scale operations.
Such facilities are thought to be capable of producing between five and six harvests in a year, if undetected.
A Garda spokesman said the seizure was the result of a planned search of a premises in the Ard Scoil area of Athy at around 11pm on Monday night.
“The premises was found to be a fully functioning grow house and a number of items of drug cultivation paraphernalia were seized,” said the spokesman.
A 43-year-old man was arrested in the Athy area and is being questioned at Kildare Garda Station.
It is thought to be the biggest cannabis factory uncovered since last July, when €750,000 worth of plants were discovered “an elaborate growhouse” in a warehouse near Ashbourne, Co Meath.
Also in July, gardaí in Donegal seized 800 plants and 30kg of cannabis herb during planned searches of lands and a premises at Carrickboy, Ballyshannon. The total value of the haul was €1.2m.
Another €700,000 haul of cannabis plants, along with a single-barrel shotgun, was made back in May at a premises in Boytonrath, Boreen, Kileenasteena, New Inn, Co Tipperary. Local units conducted that operation.