Grass over opposite points in US city (6)
I believe the answer is:
newark
'us city' is the definition.
'Newark' can be an answer for 'city' (Newark is an example). I'm not sure about the 'us' bit.
'grass over opposite points' is the wordplay.
'grass' becomes 'nark' (I've seen this before).
'over' indicates putting letters inside.
'opposite points' becomes 'ew' (east and west, two compass points. I am not sure about the 'opposite' bit.).
'nark' placed around 'ew' is 'NEWARK'.
'in' is the link.
Can you help me to learn more?
(Other definitions for newark that I've seen before include "US port" , "Notts. town; NJ city" , "Town on river Trent where King John died" , "US gateway" , "Nottinghamshire town" .)