A spokesman had said that the house was closed for the rest of today (October 3) due to 'unforeseen circumstances'.West Yorkshire Police have confirmed that officers were called to reports of a suspect package delivered in the post.
A spokesman for the force said: "At 12:20pm today (3/10), police received a report of a suspect package delivered in the post to Harewood House.
"Emergency services are attending the scene to recover the item for examination.
"Harewood House is currently closed."
What is Harewood House?
According to the house's own information: "Harewood sits in the heart of Yorkshire and is one of the Treasure Houses of England. The House was built in the 18th century and has art collections to rival the finest in Britain.
"Visitors can enjoy exhibitions of contemporary art, rare Bird Garden, Farm Experience and over 100 acres of exquisite gardens to explore.
"Be part of the living history and visit Harewood House."