Near a city · The Castle Rolls
Castles near London
20 castles sit within 40 miles of London - the Tower itself is on the doorstep, with Windsor, Hever and Leeds Castle further out into Berkshire and Kent.

Map
Every castle on this list - 20 in total, 6 free to enter, 3 you can stay overnight in

Tower of London
Greater London · 2 mi away
Crown Jewels; Yeoman Warder tours
Photo: [Duncan] from Nottingham, UK, CC BY 2.0, via Wikimedia Commons, cropped

Lullingstone Castle
Kent · 17 mi away
World Garden; seasonal opening
Photo: Marathon, CC BY-SA 2.0, via Wikimedia Commons, cropped

Eynsford Castle
Kent · 17 mi away Free entry
Photo: Richard Nevell from London, United Kingdom, CC BY-SA 2.0, via Wikimedia Commons, cropped
Windsor Castle
Berkshire · 21 mi away
Working royal residence

Hever Castle
Kent · 24 mi away
B&B in Astor Wing
Photo: Christoph Matthias Siebenborn, CC BY 3.0, via Wikimedia Commons, cropped

Chiddingstone Castle
Kent · 25 mi away
Houses Denys Eyre Bower collections

Berkhamsted Castle
Hertfordshire · 26 mi away Free entry
Managed with Berkhamsted Castle Trust; open daily
Photo: Dr John Wells, CC BY 4.0, via Wikimedia Commons, cropped

Guildford Castle
Surrey · 27 mi away
Free grounds; keep ticketed Wed-Sat
Photo: Richard Nevell from London, United Kingdom, CC BY-SA 2.0, via Wikimedia Commons, cropped

St Leonard's Tower
Kent · 27 mi away
Early Norman tower keep; exterior viewing

Tonbridge Castle
Kent · 28 mi away
Free grounds; ticketed gatehouse experience
Photo: Clem Rutter, Rochester Kent, CC BY-SA 3.0, via Wikimedia Commons, cropped

Rochester Castle
Kent · 28 mi away
EH property managed day-to-day by council; also listed under English Heritage
Photo: Stephencdickson, CC BY-SA 4.0, via Wikimedia Commons, cropped

Upnor Castle
Kent · 29 mi away
Elizabethan artillery fort; managed by Medway Council
Photo: Phil Pead, CC BY-SA 4.0, via Wikimedia Commons, cropped

Mountfitchet Castle
Essex · 31 mi away
Reconstructed Norman village on original earthworks
Photo: Acabashi, CC BY-SA 4.0, via Wikimedia Commons, cropped

Hadleigh Castle
Essex · 32 mi away Free entry
Photo: Chris Beach from London, CC BY 2.0, via Wikimedia Commons, cropped

Rayleigh Mount
Essex · 32 mi away Free entry
Norman motte-and-bailey earthworks of Rayleigh Castle
Photo: Luke Cops, CC BY 3.0, via Wikimedia Commons, cropped

Farnham Castle Keep
Surrey · 35 mi away
Keep currently closed to the public
Photo: davidhc, CC BY 2.0, via Wikimedia Commons, cropped

Scotney Castle
Kent · 37 mi away
Moated medieval Old Castle ruin below Victorian mansion

Leeds Castle
Kent · 37 mi away
Maiden's Tower and B&B stays on site
Photo: Adusha, CC BY 3.0, via Wikimedia Commons, cropped

Sutton Valence Castle
Kent · 37 mi away Free entry
Photo: Ukiws, CC BY-SA 3.0, via Wikimedia Commons, cropped

Odiham Castle
Hampshire · 40 mi away Free entry
King John's octagonal keep, free access
Photo: BabelStone, CC BY-SA 3.0, via Wikimedia Commons, cropped
Distances are straight-line ("as the crow flies"), not driving or train time - check the operator's own site for real travel options before you go.
Common questions
How many castles are there within 40 miles of London?
This roll lists 20 visitable castles, fortresses and tower houses within 40 miles of London. Of those, 6 are free to enter and 12 charge admission. The other 2 have restricted access.
Which castles within 40 miles of London are free to visit?
6 of the 20 castles within 40 miles of London are open-access sites with no admission charge, namely Eynsford Castle, Berkhamsted Castle, Hadleigh Castle, Rayleigh Mount, Sutton Valence Castle and Odiham Castle.
What is the best-rated castle within 40 miles of London?
Hever Castle is among the highest-rated castles within 40 miles of London on this roll - 4.8/5 from 13,800 Google reviews.
Can you stay overnight in a castle within 40 miles of London?
Yes - 3 of the castles listed here offer overnight stays, namely Hever Castle, Scotney Castle and Leeds Castle.
Can you reach any castle within 40 miles of London by train?
17 of the 20 sit within 1.5 miles of a railway station, the closest being Mountfitchet Castle (Stansted Mountfitchet, 0.1 miles), Berkhamsted Castle (Berkhamsted, 0.1 miles), Windsor Castle (Windsor & Eton Riverside, 0.2 miles) and Rayleigh Mount (Rayleigh, 0.2 miles). Those are straight-line distances from the station to the castle, so the walk on the ground is longer than the figure.
Can you go inside every castle within 40 miles of London?
Not all of them on the same terms. 2 of the 20 restrict what a visitor can see. At St Leonard's Tower and Farnham Castle Keep the building itself isn't open to visitors, so you see it from the grounds or from outside.