Following Gloucester's usurpation and death (1483–85), the castle and the town remained part of the Crown Estate until the reign of William III who gave it and most other Crown property in Cumberland to his friend Hans Willem Bentinck, 1st Earl of Portland in 1696.
 The castle was sold by the Earls and Dukes of Portland to the Dukes of Devonshire in 1787.
They later sold it to the Lancaster & Carlisle Railway Company who built Penrith railway station; its remains are opposite the railway station today.
It later passed into the ownership of the Penrith Urban District Council, who in the 1920s converted the grounds into a public park and built housing nearby.
The few ruins that remain today were described in the nineteenth century as not 'very interesting in respect of their antiquity, or their present appearance.'
Also, very much as they stand today:
The ruins are remarkable more for their extent than their magnificence: the chief objects of interest are the projecting corbels in the eastern front, which appear to have supported an open corridor; there are some large vaults, which were probably prisons.
The walls, broken in many places, and intersected with remaining windows, assume, from different points of view, striking varieties of perspective scenery.
After the great civil war, the edifice was dismantled, and part of the materials sold.

The castle is maintained by English Heritage, and is recorded in the National Heritage List for England as a designated Grade I listed building.
Following Gloucester's usurpation and death (1483–85), the castle and the town remained part of the Crown Estate until the reign of William III who gave it and most other Crown property in Cumberland to his friend Hans Willem Bentinck, 1st Earl of Portland in 1696.  The castle was sold by the Earls and Dukes of Portland to the Dukes of Devonshire in 1787. They later sold it to the Lancaster & Carlisle Railway Company who built Penrith railway station; its remains are opposite the railway station today. It later passed into the ownership of the Penrith Urban District Council, who in the 1920s converted the grounds into a public park and built housing nearby. The few ruins that remain today were described in the nineteenth century as not 'very interesting in respect of their antiquity, or their present appearance.' Also, very much as they stand today:
The ruins are remarkable more for their extent than their magnificence: the chief objects of interest are the projecting corbels in the eastern front, which appear to have supported an open corridor; there are some large vaults, which were probably prisons. The walls, broken in many places, and intersected with remaining windows, assume, from different points of view, striking varieties of perspective scenery. After the great civil war, the edifice was dismantled, and part of the materials sold.
The castle is maintained by English Heritage, and is recorded in the National Heritage List for England as a designated Grade I listed building.
Penrith Castle