The 71-year-old 'Raging Bull' star purchased his Hudson Valley pad via his Riverside Trust in 1997 for USD 1.5 million, but expanded the estate in recent years to include two guest houses, a swimming pool, basketball court, boxing space and film production suites, reported New York Times.
The extensive renovations prompted tax officials to revalue the property at USD 6 million in 2010, and De Niro challenged the estimation, insisting it was only worth USD 4 million.
He has since reached a settlement with the local authorities in Gardiner and agreed to drop the appeal and pick up the bill for costs they incurred while defending their assessment.