European route E 661 is a part of the inter-European road system. This Class B north–south route is long and it connects Lake Balaton in Hungary via western Slavonia in Croatia with Bosanska Krajina and central Bosnia.
Itinerary The E 661 routes through three European countries:
: Balatonkeresztúr () - Nagyatád - Barcs
: Terezino Polje - Virovitica - Grubišno Polje - Daruvar - Pakrac - Lipik - Okučani () - Stara Gradiška
: Gradiška - Banja Luka : Banja Luka - Jajce (Start of Concurrency of ) - Donji Vakuf : Donji Vakuf - Travnik - Zenica ()
External links UN Economic Commission for Europe: Overall Map of E-road Network (2007)