Opaka is a town in Targovishte Province in northeast Bulgaria. As of December 2009, the town had a population of 2,873 and covers an area of 57 square kilometres (22 sq mi). It is 70 kilometres (43 mi) south of the city of Rousse on the border with Romania and 250 kilometres (160 mi) northeast of the Bulgarian capital, Sofia. Archeologists have found evidence of Thracian, Roman and Slavonic settlements in the area. Near the village of Krepcha, a stone monastery is the site of the oldest known Old Bulgarian Cyrillic inscription, dated from around 920 CE. A 2nd century Thracian tumulus containing various artifacts, including six leaves of a golden wreath and bronze figurines, was excavated in 2011.