Trilj is a town and settlement in inland Dalmatia, Croatia. It is located northeast of Split. In 2021, its population was 8182. Trilj was a traffic …Trilj is a town and settlement in inland Dalmatia, Croatia. It is located northeast of Split. In 2021, its population was 8182. Trilj was a traffic hub in Roman times, when a stone bridge Pons Tilurium was built on the Cetina River. A 7th Roman legion military camp called Tilurium was built on a hill above, at the crossroads of Roman roads leading from Salona to Narona and Bosnia.