1. The Drowning Pool Leigh-on-Sea (Southend)

2. Where is Leigh-on-Sea? In the region of East Anglia...

3. ...and in the county of Essex
Essex is a county in the UK and is the home county northeast of the city of London. It borders the counties of Suffolk and Cambridgeshire to the north, Hertfordshire to the west, Kent across the estuary of the River Thames to the south and London to the southwest.

4. Southend-on-Sea, a few pics

5. A few words about Southend
Southend became a seaside resort during the Georgian era, attracting many tourists in the summer months to its seven miles of beaches and bathing in the sea.
Good rail connections and proximity to London mean that much of the economy has been based on tourism, and that Southend has been a dormitory town for city workers ever since. 
Southend Pier is the world's longest pleasure pier at 1.34 mi (2.16 km).[2] It has suffered fires and ship collisions, most recently in October 2005,[4] but the basic pier structure has been repaired each time.

6. But what about Leigh-on Sea?
Leigh-on-Sea can be found on the South Coast of the British Isles approximately 35 miles from London, in the County  of Essex. Leigh is part of Southend. 
Leigh is a picturesque town built on the Thames Estuary full of sandy beaches and with amazing views from ‘the cliffs’ ...

7. ...The Cliffs

8. Leigh was originally a fishing village

9. Old Leigh, the heart of The Drowning Pool
It then gradually reverted to a fishing village, supplying the London market by road and barge. 
By the 16th century Leigh had become a fairly large and prosperous port. Ships of up to 340 were built in Leigh. They say the Mayflower was built here.
By the 18th century ships had become larger and trade changed. At this time Leigh's deep water channel silted up and the importance of the town diminished.
It then gradually reverted to a fishing village, supplying the London market by road and barge. 

10. Old Leigh, nowadays... (P19, P49...)

11. Some places mentioned in TDP... Hadleigh Castle (P9)

12. ... The Crooked Billet (P81)

13. ...and ‘the lane full of cockle sheds out side the Crooked Billet pub’ (P81)

14. The Peter Boat
(...) Her speciality was lace and skills. Sarah Grey had a shop by the Peter Boat. (P211).

15. The Broadway (P8, P48...)

16. Bell Wharf & The Smack (P13-14)
‘Sarah Grey would sit on the edge of Bell Wharf (...) until the captain of The Smack came along’ Nowadays, ‘Ye olde Smack’ is a pub in Old Leigh.

17. The Doom Pool in Leigh Road

18. ...The Doom Pool... Opposite The Broker Pub, now appartments

19. St Clements’ Graveyard (P173, P211...)
Reverend Eden had been rector of St Clements’, where most of the ‘witches’ might be buried.

20. ... And locals in the book...
The ‘ugly’, Sarah Moore,(Sarah Grey in the book) the sea witch who sold a ‘fair-wind’ to seamen as a means of support for her and her children. Incidentally, those foolish enough not to cross her palms with coins received a curse, one such curse is still reputed to be in existence today on one old Leigh family. (P13, P154...)

21. Lady Olivia Sparrow
 Ireland,  she was the daughter of Arthur Acheson, 1st Earl of Gosford. Olivia and Robert married on 14th March 1797 at Dublin and lived at Brampton Park in Huntingdonshire. They had three children
Lady Olivia Sparrow inherited her estates at Leigh and Hadleigh through her husband’s mother, 
Lady Olivia Sparrow was an extremely religious woman and had a deep seated belief in the education and care of the poor. During the early 19th century there was no formal education system, so the vast majority of poor children were therefore deprived of schooling. In 1834 she opened a church day school in Leigh.
The children of Hadleigh were also admissible to the school, and thus Lady Sparrow ensured that many of the poorer children of Hadleigh and Leigh were taught to read and write.