Hilborn, who also coaches Mildenhall Town U18s, has previous senior coaching experience in the Cambs County League and is currently working towards completion of the UEFA B Coaching Licence.
Guy Habbin, Haverhill Borough's First Team Manager said "We're delighted to have acquired Dean as part of our staff here at Borough. Dean is a real student of the game and eager to support myself and Mark (Hammond, Assistant Manager) as much as possible."
Borough, who currently sit in 17th place in Thurlow Nunn Division 1 travel to 18th place Sheringham on Saturday (3pm kick off).