Bother after company curtailed lord in US State (8)
I believe the answer is:
colorado
'us state' is the definition.
(I've seen this before)
'bother after company curtailed lord' is the wordplay.
'bother' becomes 'ado' (I've seen this before**).
'after' means one lot of letters go next to another.
'company' becomes 'co' (abbreviation).
'curtailed' means to remove the last letter.
'lord' with its final letter taken off is 'lor'.
'co'+'lor'='color'
'ado' put after 'color' is 'COLORADO'.
'in' is the link.
(Other definitions for colorado that I've seen before include "US state, W. of Kansas" , "Denver's state" , "Beetle whose larvae destroy potato plants" , "US state has a cool road, oddly" , "US state has a strangely cool road" .)