Petrich ( ) is a town in Blagoevgrad Province in southwestern Bulgaria, located in Sandanski–Petrich Valley at the foot of the Belasica Mountains in the Strumeshnitsa Valley. According to the 2021 census, the town has 26,778 inhabitants. It is the seat of Petrich Municipality. Petrich is located close to the borders with Greece and North Macedonia. The crossing into North Macedonia is known as Novo Selo-Petrich, as the first settlement across the border is Novo Selo. Petrich Peak on Livingston Island in the South Shetland Islands, Antarctica is named for Petrich. History Petrich was included in the territory of the Bulgarian State during the reign of Knyaz Boris I (r. 852–889). During the Middle Ages it was a Bulgarian fortress of importance during Tsar Samuil's wars (r. 997–1014) with Byzantium. During Ottoman rule, it formed part of the Rumeli Eyalet, and in the 19th century became a kaza of the Sanjak of Serres in the Salonica Vilayet. From 19 January 1892, Petrich and its district were included in the Bulgarian Exarchate, before being included in Bulgaria following the Balkan Wars in 1912–13. In October 1925 it was the site of a brief conflict between Greece and Bulgaria sometimes called the War of the Stray Dog. Antiquity Petrich is one of the old towns in the valley of the middle Struma. According to local historians, the present-day town of Petrich is the heir to the ancient Thracian settlement located at the southern foot of the Kozhuh hill. In this area, located 10 km northeast of the modern city, in the 4th century BC, a Thracian settlement of the Medi tribe emerged. In the 1st century BC. the Romans conquered the lands of the Medes and then the small settlement near Kozhuh became a well-fortified Roman city - a fortress that protected the middle reaches of the Struma and Rupel gorge. According to the interpretation of the Roman historian Titus Livy, it is assumed that this city was called Petra. Archaeological excavations show that it existed until the 6th century, when it was burned by the Slavs. It is assumed that the remaining living inhabitants left the burned town and settled at the foot of the nearby mountain Belasitsa, which marked the beginning of today's town of Petrich, adding to the old name the Slavic ending "-ich". Recent archaeological research and the location of the ancient city of Heraclea Sintica in the