Located at Ponders End, tied in a knot (5)
I believe the answer is:
sited
'located' is the definition.
('site' can be a synonym of 'locate')
'ponders end tied in a knot' is the wordplay.
'end' says to take the final letters.
'in a knot' indicates an anagram.
The last letter of 'ponders' is 's'.
'tied' anagrammed gives 'ited'.
's'+'ited'='SITED'
'at' acts as a link.
(Other definitions for sited that I've seen before include "installed" , "Positioned" , "Placed, located" , "Put" , "Situated" .)