Polesden Lacey was left to the National Trust by Mrs Greville in 1942 in memory of her father, the brewer William McEwan (she was his illegitimate daughter and sole heir).
The bequest included approximately 1,000 acres (400 ha) of land along with paintings and items of furniture, which she hoped would form the basis of a future art gallery.
The house was first opened to the public by the Trust in August 1946.

In August 1960, a fire destroyed around half of the roof of the property.
Several ground floor ceilings were damaged by water during attempts to extinguish the blaze, however the collection of art and furniture was rescued by estate workers.
The cost of repairs, some £65,000, was covered by insurance and the house reopened to the public on 9 June 1962.

In 1995 the National Trust embarked on a programme of restoration and renovation.
In 2008/9 the visitor facilities were fairly extensively re-furbished, with a new car park, cafe, shop and farm shop.
It received 347,149 visitors in 2018, placing it in the Trust's top ten most-visited properties.

Some areas of the house are not currently open to the public.
This is because in 1942 it was thought that the bedrooms and servants' areas would not be of interest to visitors.
 The first floor of the mansion is used by the National Trust Regional Office for London and the South East.
The old servants' areas (on the ground floor) are used by the Polesden Lacey staff as offices.
In the future, it is hoped that more of the mansion will be open to the public.
This began in March 2011 with the opening of Mrs Greville's private apartment which had been occupied by the House Manager.
The house is open to the public all year round except for Christmas Eve and Christmas Day.
On weekday mornings admission is via a short themed tour.
By March 2016 the Regional staff were beginning to move out, allowing more rooms to be available for public viewing.

There are a number of walks around the Polesden Lacey estate, especially in the valley that the main house overlooks.
 The estate includes a Youth Hostel, Tanners Hatch.

The re-modelling of the facilities in 2008–2009 means that the cafe and shop (as well as the walks) can now be accessed without paying for admission.

Polesden Lacey also has open-air performing facilities, which are used during the summer to host various musical and theatrical events.
In 2009 there was the Polesden Lacey Festival.
Polesden Lacey was left to the National Trust by Mrs Greville in 1942 in memory of her father, the brewer William McEwan (she was his illegitimate daughter and sole heir). The bequest included approximately 1,000 acres (400 ha) of land along with paintings and items of furniture, which she hoped would form the basis of a future art gallery. The house was first opened to the public by the Trust in August 1946.
In August 1960, a fire destroyed around half of the roof of the property. Several ground floor ceilings were damaged by water during attempts to extinguish the blaze, however the collection of art and furniture was rescued by estate workers. The cost of repairs, some £65,000, was covered by insurance and the house reopened to the public on 9 June 1962. 
In 1995 the National Trust embarked on a programme of restoration and renovation. In 2008/9 the visitor facilities were fairly extensively re-furbished, with a new car park, cafe, shop and farm shop. It received 347,149 visitors in 2018, placing it in the Trust's top ten most-visited properties.
Some areas of the house are not currently open to the public. This is because in 1942 it was thought that the bedrooms and servants' areas would not be of interest to visitors.  The first floor of the mansion is used by the National Trust Regional Office for London and the South East. The old servants' areas (on the ground floor) are used by the Polesden Lacey staff as offices. In the future, it is hoped that more of the mansion will be open to the public. This began in March 2011 with the opening of Mrs Greville's private apartment which had been occupied by the House Manager. The house is open to the public all year round except for Christmas Eve and Christmas Day. On weekday mornings admission is via a short themed tour. By March 2016 the Regional staff were beginning to move out, allowing more rooms to be available for public viewing. 
There are a number of walks around the Polesden Lacey estate, especially in the valley that the main house overlooks.  The estate includes a Youth Hostel, Tanners Hatch.
The re-modelling of the facilities in 2008–2009 means that the cafe and shop (as well as the walks) can now be accessed without paying for admission.
Polesden Lacey also has open-air performing facilities, which are used during the summer to host various musical and theatrical events. In 2009 there was the Polesden Lacey Festival.
Polesden Lacey