A town on the Velebit Channel at the foot of the Velebit and Senjsko bilo mountain ridges. The oldest town on the northern Adriatic is semi-circular in shape, and is surrounded by high hills on three sides and by the sea on the fourth. It has become the most important town between Rijeka and Zadar. Its significance is mainly due to the land connection between the coast and the interior. In the winter, Senj is the coldest town on the Adriatic due to the frequent rushes of cold continental air across the Vratnik Pass. South of Senj lie bays with beautiful beaches. This was the site of an important prehistoric llyrian settlement.

In the 4th century, it was known by the Greeks as the town of Senia. In the Roman era, it was the main fortified commercial port serving as a connection with the interior. In the medieval Croatian state, it became important when a diocese was established here in 1154. The Frankopans assumed control over Senj in 1271 and began to build a wall and defence towers. The Hungarian King Mathias Corvinus occupied it in 1469 and declared it a royal town and the seat of the captaincy, which was the seed of the Croatian Military Frontier. After 1526 the town was ruled by the Habsburgs. In that period, it was surrounded by new fortifications, the inner part of town was surrounded by a wall, and the magnificent Nehaj Fortress was built on a hill above the town.

The Uskoki, refugees from the areas occupied by the Turks, began to move to Senj in 1527. The Austrians accepted them as experienced soldiers who could defend the Military Frontier. For an entire century, Senj was the main military stronghold in the battles against the Turks and the Venetians. After the 1615 war between Austria and Venice, they had to move out. Between 1809 and 1813, Senj was part of Napoleon's lllyrian Provinces, followed by the Military Frontier again. In 1871, it became part of Croatia. After the fall of Yugoslavia in 1941, it was occupied by the Italian army. After Italy's capitulation in 1943, it was bombed by German planes and severely damaged.

The numerous cultural and historical monuments in Senj include the Sabac kula (13th century) and Papinska kula (1513-21) towers, the Renaissance Church of sv. Marija (St. Mary) on the Art Square, the town castle from around 1340, the large town gate, the fountain on the main square, and the Cathedral of sv. Marija (St. Mary) from 1248 on the old square. Other attractions include the preserved part of the defence wall with towers, numerous portals and individual houses. A special attraction of Senj is the Nehaj Fortress on the Trbusnjak hill. It was built in 1558, when the Turkish and Venetian military power was at its peak. Senj resisted both and remained free. The commander of the Senj Uskoki, Ivan Lenkovic, ordered the destruction of all churches and monasteries outside the town wall and used the material to build a fortress, which was unassailable at the time. There is a viewpoint at the top of the fortress.

The port is not safe when northwesterly or westerly winds blow, and it is also not recommended when the bora blows. Berths are available at all three piers and breakwaters. There is a 10-ton lift. The Ujca campsite has a small harbour.