D.300 is a major eastâÂÂwest state road spanning through central Turkey. The route begins in ÃÂeà Âme, ðzmir and runs east to Kapñköy, Van, on the Turkey-Iran border. The route connects several provincial capitals, including ðzmir, Uà Âak, Afyon, Konya, Aksaray, Kayseri, Malatya, ElazñÃÂ, Muà  and Van. The route is the second longest state highway in Turkey, after the D.400.
The D.300 is a four-lane highway for most of the route, except for two short sections toward the western end. The route becomes a controlled-access highway within ðzmir.