The city of Sofia is the centre of the Southwestern Region and the capital of Bulgaria. Administratively Sofia District is divided into 24 municipalities. The city of Sofia has a population of 1 127 000 inhabitants. Sofia is located in the Sofia field at an altitude of 550 m at the foot of Vitosha Mountains.

At the site of an ancient neolith settlement a new ancient Thracian town appears. The settlement develops around the hot mineral springs situated at the centre of Sofia. The town gets its name from the Serdi Thracian tribe and is named Serdika.

The town is conquered by the Romans in I century. During the III c. it becomes the centre of Internal Dakia Province. The Roman emperor Mark Ulpii Trayan adds the name Ulpia to the town and gives it the same rights as all the big towns in the eastern provinces. The emperor Konstantin the Great calls Serdika "My Rome". During the reign of Justinian the great Serdika has its final zenith within the limits of the Eastern Roman Empire. From ancient Serdika are preserved remains from the bath with the captured hot water-conduit, the eastern and western town gates, sarcophagi, streets etc. From the early Christian times are preserved the Rotunda ("St. George") and "St. Sofia" Church. The Christian holiday commemorating Saint Sofia and her daughters Vyara/Faith/, Nadezhda /Hope/ and Lyubov /Love/ is the town's holiday. The town enters the limits of Bulgaria in 809 and gets the name of Sredetz and after the fall of the town in Byzantine hands it is named Triaditza. In 1183 Serbians and Madzhars plunder the town as later on do the crusaders of Fredrik I Barbados. From the medieval period in Sofia is preserved the Boyana Church which is among the significant monuments of the Bulgarian Middle Ages. It is included in the UNESCO Cultural Heritage List. There are more than 90 monasteries in the vicinity of present day Sofia. Most of them date back to XI-XIV c. The most well-preserved among them are "St. Nikolai Mirakliiski" near Malamovo with mural paintings from XVI c., "St Georgi" near Kremikovtzi, "St. Atanasii -The Alexandrian" near Nedelishte, "Sveta Bogoroditza"/Holy Virgin/ in Dragalevtzi built in 1354 by King Ivan Alexander. Sofia falls under the Ottoman Yoke in 1384. In present day Sofia are preserved two mosques from the period of the yoke. One of them is known as Buyuk Mosque built during 1451-1453 which is turned into an archaeological museum. The other mosque Bani Bashi Mosque from 1576 is situated opposite the Central Market Place/The Central Halls/ and continues to function as a mosque.

After the Liberation of the Ottoman yoke Sofia has a population of 20 000 inhabitants. The town is chosen for a capital in 1879. The fast development of the capital in territorial and demographic aspect dates back to the World War I. After the Liberation are built: the temple-monument "Alexander Nevski" in 1924, the Central Military club, the National Assembly, the "Ivan Vazov" National Theatre, the Chamber of Synods, The Clerical Academy, the Central Covered Market place and other important buildings. As a token of gratitude towards the Russian soldiers are built many monuments. The monument of Tsar Osvoboditel/ the Liberator King/ is the work of the Florentine Arnaldo Dzoki and is built in 1907. The doctors' monument from 1883 is built to commemorate doctors and hospital attendants from the Russian-Turkish War from 1877-1878.

Today Sofia is a political, economic and cultural centre. A great number of other settlements from the Sofia Valley gravitate around it forming the big city agglomeration.

On the territory of Sofia district are located the following natural landmarks: "Vitosha" Natural Park, part of "Rila" Natural park, part of the ‘Central Balkan" Natural park, "Uchilishna Gora" Reserve, "Bogdan" Reserve/in Sredna Gora Mountains/, Marichini Lakes/ in Rila Mountains/ and the Lakatnik Rocks. The most famous rocky phenomena on the territory of the district are: "The Jungle", "The Sopolivi Skali", "Orlovi Skali", "Lopyanski Kuli". Within the administrative region of Sofia lie the following monasteries: Seslavski, Lozenski, Dragalevtzi, Iliyanski, Dolnopasarelski, Kremikovski, Kurilovski, Eleshinishki, Samokovski, Alinski, Etropolski, Osenovlashki, Iskretzki and many other.