Otočac is a town and municipality in the Croatian province Lika-Senj. Otočac counts 10.411 residents in an area of 565,3 km².
Otočac was named after the early Croatian parish. The text of the famous Baška Tablet (around 1100) says that the church of St. Nicholas in Otočac was part of the order community with the Church of St. Lucy, Jurandvor on the island of Krk. From 1300 on, it belonged to the estate of the Frankopan family. Sigismund Frankopan (1461–1535) founded a diocese there. The settlement with a defence tower, at a bend in the river Gacka, was protected by a towered fort. Only a few parts remained preserved after the fort's demolition in 1829. To provide a safer defence, a Renaissance-era castle ('Fortica') was built in 1619, with a triangular layout of cylindrical towers (these ruins stand above the town).
The Baroque parish church of the Holy Trinity, erected in 1684 and restored in 1774, is a large building with a rounded sanctuary, three side chapels are on each side of the nave. The bell tower rises from the main front. The late baroque and classicist furnishings of the church include seven altars, a pulpit, baptismal font and sepulchral slabs from the 18th century.
From 1746, Otočac was the headquarters of the Ottotschaner Grenz-Infanterie Regiment N°II, part of the Croatian Military Frontier, (Croatian Vojna Krajina). A number of harmonious, simple, mostly two-story houses originate from this period. Until 1918, Otočac was part of the Austrian monarchy (part of the Kingdom of Croatia-Slavonia subordinate to the Kingdom of Hungary after the compromise of 1867). In the late 19th century and early 20th century, Otočac was part of the Lika-Krbava County of Croatia-Slavonia.
