State that's just north of Washington and New York (6)
I believe the answer is:
canada
'york' is the definition.
Both the definition and answer are singular nouns.
Perhaps there's an association between them I don't understand?
'state that's just north of washington and new' is the wordplay.
'state' becomes 'ca'.
'that's just north of washington' becomes 'ada' (I am not sure about this - if you are sure you should give a lot more credence to this answer).
'and' means one lot of letters go next to another.
'new' becomes 'n' (common abbreviation eg NT for New Testament).
'ada' after 'n' is 'nada'.
'ca'+'nada'='CANADA'
(Other definitions for canada that I've seen before include "N American country" , "N.American nation" , "North American country" , "Land of the Great Lakes" , "Part of North America" .)