M4 motorway entrance will close permanently on Friday.
Access routes to Castletown House are to change next week, but the building and the 225 acres of parklands will remain fully open to visitors.
The Office of Public Works have announced the M4 motorway entrance will close permanently on Friday.
Car access will be via the Celbridge Avenue entrance only.
Pedestrian and cycle access via the Batty Langley Gate will continue as normal.
New visitor car park facilities are being installed at the Celbridge Gate, including enhance amenities for cyclists and disabled drivers.
The OPW says Castletown is one of their most visited heritage sites in Ireland.