Rijeka is located in western Croatia, south-west of the capital, Zagreb, on the coast of Kvarner Gulf (), in the northern part of the Adriatic Sea. Geographically, Rijeka is roughly equidistant from Milan (), Budapest (), Munich (), Vienna () and Belgrade (). Other major regional centers such as Trieste (), Venice () and Ljubljana () are all relatively close and easily accessible. The Bay of Rijeka, which is bordered by Vela Vrata (between Istria and the island of Cres), Srednja Vrata (between Cres and Krk Island) and Mala Vrata (between Krk and the mainland) is connected to the Kvarner Gulf and is deep enough (about ) to accommodate large commercial ships. The City of Rijeka lies at the mouth of river Rječina and in the Vinodol micro-region of the Croatian coast. From three sides Rijeka is surrounded by mountains. To the west, the Učka range is prominent. To the north/north-east there are the Snežnik plateau and Risnjak () massif with the national park. To the east/south-east there is the Velika Kapela range. This type of terrain configuration prevented Rijeka from developing further inland (to the north) and the city mostly lies on a long and relatively narrow strip along the coast. Two important inland transport routes start in Rijeka. The first route runs north-east to the Pannonian Basin. This route takes advantage of Rijeka's location close to the point where the Dinaric Alps are the narrowest (about ) and easiest to traverse, making it the optimal route from the Hungarian plain to the sea. It also makes Rijeka the natural harbour for the Pannonian Basin (especially Hungary). The other route runs north-west across the Postojna Gate connecting Rijeka with Slovenia and further through the Ljubljana Gap with Austria and beyond. A third more coastal route runs east-west connecting Rijeka (and—by extension—the Adriatic coastal cities to the south) with Trieste and northern Italy.