Shurdhah Island is located in the Vau i Dejës Reservoir, which is fed and drained by the river Drin.
Sarda was founded between the 6th and 7th centuries. The town was strategically located on the old road from the Adriatic Sea to Dardania and served as a resting point along the trade route. The settlement originally had a wall encircling the entire hill it was built on. Encircled on three sides by the Drin river, Sarda had 12 towers of various forms. Sarda seems to have been a modest settlement from its foundation to the 9th century when it saw rapid expansion. It gained its highest importance in the 12th century, when it was the seat of the joint bishop of Sapa and Sarda. Around 1100 a Diocese of Sarda was established on the island.
The island was the original settlement of the feudal Lekë Dukagjini patriarch, famous for the rules of the Kanun. It was ravaged by the Ottomans in 1491.
Today tourists can visit the ruins of the 11th-century medieval castle, which includes two rings of defensive walls and towers (some sadly submerged in the lake), the remains of a Byzantine church and other early medieval walls. The setting on the steep rocks rising from the lake is especially impressive. The island is accessible by tourist boat in summer from the Vau i Dejës dam or Rragam.