Harshness of way to travel about in state in America (9)
I believe the answer is:
stridency
'harshness' is the definition.
(strident can mean harsh-sounding)
'way to travel about in state in america' is the wordplay.
'way to travel' becomes 'stride' (striding is a way of moving or travelling ).
'about' becomes 'c' (abbreviation for 'circa').
'in' means one lot of letters goes inside another.
'state in america' becomes 'ny' (New York).
'c' placed inside 'ny' is 'ncy'.
'stride'+'ncy'='STRIDENCY'
'of' acts as a link.
(Other definitions for stridency that I've seen before include "Harshness" , "Clamour" , "Loud and harsh quality" .)