The discovery was made in Longford yesterday morning.
Gardaí from Granard working alongisde the local Regional Support Unit, the Garda Stolen Motor Vehicle Investigation Unit, The National Bureau of Criminal Investigation and The Longford Drugs Unit carried out a search operation in Co. Longford on November 29.
The search uncovered a large amount of suspected stolen industrial plant, tools, trailers, vans, cars, engines and car parts with an initial estimate worth up to €500,000.
Some items found were identified as being stolen in the UK over the past few months.
Gardaí are continuing to try and establish the origin of the rest of the property.
The scene is currently preserved and the technical examination continues.
There were no arrests and the investigation is ongoing.