After the Treaty of San Stefano the whole area became part of Bulgaria, but after the Treaty of Berlin the region was returned under Ottoman rule. In 1894 was erected the Bulgarian Orthodox bishopric of Nevrokop with a seat in Nevrokop. In 1903 the region took part in the Ilinden–Preobrazhenie Uprising. During the First Balkan War volunteers joined Macedonian-Adrianopolitan Volunteer Corps. After the war the region left in Bulgaria. Most of the Greek population fled to Greece. Some Turkish and Muslim people also moved out. Refugees from the parts of Macedonia, that were left outside Bulgaria came to live here, so the ethnic character of the population changed. There was a process of forced converting of the Muslim people in The Bulgarian part of Macedonia to the Christianity, sponsored and inspired by the Bulgarian government and Bulgarian Orthodox Church and performed by IMRO, but with no actual further results. In 1922 forces of the Macedonian Federative Organization with the support of the Bulgarian government attacked the IMRO local detachments. As result of this unrest on October 17 Nevrokop was occupied by forces of IMRO, who banished the Federalists, but with no further serious consequences. In the years of the Bulgarian resistance movement during World War II a formation led by Aneshti Uzunov operated in the region. After his death in 1943 it was named after him. After the Bulgarian coup d'état of 1944 many activists of IMRO from the area were assassinated or imprisoned or fled abroad. In 1951 Nevrokop was renamed after the revolutionary Gotse Delchev.