Country swamping the river in neon lights (11)
I believe the answer is:
netherlands
'country' is the definition.
(Netherlands is an example)
'swamping the river in neon lights' is the wordplay.
'swamping' means one lot of letters goes inside another (swamp can mean to surround or smother).
'river' becomes 'r' (abbreviation).
'in' means one lot of letters goes inside another.
'neon' becomes 'Ne' (Ne is the chemical symbol for neon).
'lights' becomes 'lands' (I can't explain this - if you can you should give a lot more credence to this answer).
'ne'+'lands'='nelands'
'r' inserted into 'nelands' is 'nerlands'.
'the' inserted within 'nerlands' is 'NETHERLANDS'.
Can you help me to learn more?
(Other definitions for netherlands that I've seen before include "- Antilles includes island of Curacao" , "somewhere in Europe" , "Their government at The Hague" , "North European country" , "European kingdom, capital Amsterdam" .)