Where shanty men were bound to go (3,6)
I believe the answer is:
rio grande
'where shanty men' is the definition.
Although both the answer and definition are singular nouns, I don't see how one could define the other.
'were bound to go' is the wordplay.
I cannot really understand how this works, but
'were' could be 'ran' (running is a kind of being) and 'ran' is found within the answer.
This explanation may well be incorrect...
Can you help me to learn more?
(Other definitions for rio grande that I've seen before include "US/Mexican border river" , "River flowing between USA and Mexico" , "Great river bordering USA and Mexico" , "River boundary between the US and Mexico" , "American flower" .)