Rila is the highest mountain in Bulgaria and on the whole Balkan Peninsula. It occupies the prestigious 6th place in the European “classification”, preceded by: Caucasus (Mt. Elbrus - 5642 m), the Alps (Mt. Mont Blanc - 4807 m), Sierra Nevada (Mt. Mulasen - 3482 m), the Pyrenees (Mt. Aneto - 3404 m) and the Etna volcano (3340 m). It is a central mountain for the peninsula and it is a main orographic and hydrographic junction. It is a composite part of the Rila - Rhodope Massif and occupies its north-western end.
The oldest name of the mountain is Dounkas, given to it by the Thracians. It means a place with a lot of water. Thracian is its other name Roula, which was altered by the Slav to Rila. It is also related to the water abundance of the mountain (it means “water mountain”).
The key constructive element in the mountain is granite. There are also marble, crystalline schists and others here. The twofold glaciating of Rila played an important part in the formation of its relief. The multitude of cirques, the well outlined trog (glacial) valleys, the Alpine peaks and the glacial lakes are evidence for this.
The climate of Rila is determined by its geographical situation, on the border between the continental and the transitional Mediterranean climate and the microclimate - by the altitude zones and by the soil and vegetation cover. The lowest average monthly temperature was recorded during the month of February on the mount of Moussala - 11.6°С below zero. The absolute minimal temperature so far in Bulgaria was measured in the same place - 31.2°С below zero (during February). During the month of August the average temperature of the mount is 5.4°С and the absolute maximal temperature measured on Moussala is 18.7°С.
The winds in Rila blow predominantly from the west and the south-west. There are rarely north-western and north-eastern winds and they are more moderate, and the northern, southern and south-eastern winds do not play an essential role. The quantity of precipitation is significant, about 1200 mm fall on Moussala per year, about 80 per cent of them being snow. The snow cover on the parts of average altitude and the Alpine parts of the mountain often exceeds 2 metres. All these enumerated climatic factors create prerequisites, mostly in the Alpine parts of the mountain, for avalanches.
Rila has the following boundaries (clockwise): on the north - the Dzhubrena River, the Klisura Saddle and the Klisurchitsa River separate it from Verila Mountain. The Samokov Plain, the Bistritsa River, the Borovets Saddle, the Malka Slivnitsa, Slivnitsa and Maritsa Rivers (the Maritsa River up to Dolna Banya) separate it from Ihtiman Sredna Gora Mountain. Kostenets-Dolna Banya mountain valley, the Maritsa River up to its overfall with the Yadenitsa River separate Rila from the farthest south-eastern sprouts of Ihtiman Sredna Gora Mountain. On the east it borders on the Rhodopes through the Yadenitsa and Yundolska Rivers, the Yundola Saddle, Lyuta River, Avramov’s Saddle, the Dreshenets River and the Mesta River to Razlog mountain valley. On the south - Razlog mountain valley. It is separated from Pirin through the Rablevska River, Predel Saddle, and the rivers of Kulina, Elovitsa and Gradevska. On the west - the Valley of the Struma River from the overfall with the Gradevska River to the overfall with the Dzherman River. The valley of the Dzherman River from the overfall with the Struma River to the Dupnitsa Plain.
Within the so outlined borders Rila occupies the area of 2396 square kilometres.
On the basis of its orographic structures and characteristics and morphographic features the mountain is divided into 4 main parts - Eastern, Middle, North-Western and South-Western. The following rivers serve as their borders - Cherni (Black) Iskar, Levi (Left) Iskar, Beli (White) Iskar, Rilska, Iliina, Belishka and Stankova as well as the ridge saddles - Kobilino Branishte, Kadiin Grob and Gorni Kuki. Each of the main parts, on its part, is subdivided into several subparts bearing the names of the highest or central peak.
Eastern Rila is the highest (absolutely) and the most spacious of the 4 main parts and it comprises 37% of the total area of the mountain. Eastern Rila on its part is divided into 7 subparts. Three of them - the Moussala, Maritsa and Kovashki are situated on the Moussala gorge and the remaining 4 - Slavov’s, Belmeken, Ibur and Mustachal on the Ibur main gorge. The two main gorges cross at the junction Mt. Marishki Chal, situated at the main watershed on the Balkan Peninsula, between the water catchment areas of the Iskar, Maritsa and Mesta Rivers. The 11 highest peaks of the mountain steeper in Eastern Rila headed by Mt. Moussala (2925.4 m). The second – Mt. Malka (Little) Moussala (2902 m) is situated to the east (they are linked by the narrow rocky edge Trionite (the Saws)). The third highest and unique between the altitude of 2800 and 2900 metres – Mt. Irichek (2852 m) is next to them too. The lake groups of Moussalenski Ezera (“ezera” meaning lakes), Marichini Ezera, Ropalishki Ezera, Yakoruda Ezera and others are in this part as well. The highest lake in Rila is within the Moussala group - the Glacial Lake (2709 m), situated in the immediate proximity on the north under Mount Moussala. There are 9 tourist chalets and 2 high-mountain shelters in Eastern Rila. The highest meteorological station in South-Eastern Europe, built in 1932 is situated on the Mount of Moussala.
Middle Rila is the smallest part of the mountain - it occupies only 9% of its area. Its relief, however, is the most Alpine with the average altitude above sea level - 2077.17 m. Middle Rila has two main ridges - Skakavishko and Riletsko separated by the valley of the Rilska River. They are linked by Mt. Kanarata (The Rock) (2691м), occupying a focal place in the orohydrographic characteristics of the whole mountain, known as the “navel” of Rila. Three subparts are outlined along the Skakavishki Main Ridge - Skakav, Marinkov and Shishkov. There are 3 subparts along the Rilets Ridge, too - Kanara, Rilets and Brichebor, i.e. Middle Rila has 6 subparts. The highest peak is Mt. Karaalanitsa (Black Meadow) - 2716 m (14th highest in Rila). The following peaks are remarkable, too: Mt. Rilets (2713 m), Mt. Yosafitsa (2697 m), Mt. Aladzha Slap (2684 m), Mt. Vodniya Chal (Water Peak) (2683 m). Middle Rila is rich in glacial lakes. Here are: the Fish Lakes, Prekorech Lakes, Mermer Lakes, Karaomerish Lakes, Dzhendem (Hell) Lakes, the Monastery Lakes. The biggest glacial lake on the Balkan Peninsula - Smradlivoto (Srinking) with the area of 212 decares is also in this part of the mountain. There are 3 chalets in Middle Rila and one high-mountain shelter.
North-Western Rila, which is divided into low and high (Alpine) parts, occupies 24% of the total area of the mountain and is the third biggest in relation to the average altitude above sea level, too - 1555.73 m. Its low part comprises the oblong Govedartsi mountain valley and the so-called Lakatish Rila, which is a fore-mountain of the main massif of Rila. The high (Alpine) part is divided into Malyovitsa, Damga, Kalins, Otovish and Kabul subparts. The most prominent Alpine sites of Rila and Bulgaria are located in the Malyovitsa subpart. These are the peaks: Mt. Malyovitsa (2730 m, a symbol of Bulgarian alpinism and mountaineering), Mt. Kupenite (the highest of them – Mt. Great Kupen is the highest peak in North-Western Rila - 2731 м), Mt. Elenin, Mt. Orlovets, Mt. Zliya Zub (Evil Tooth), Mt. Dvuglav (Two-headed), Mt. Lovnitsa, Mt. Petlite (Roosters), Mt. Orleto (Little Eagle) and a number of others. Some of the biggest and significant lake groups are situated in this part of the mountain – Urdini Ezera, Malyovshki Ezera, Elenski Ezera, Gradinski Ezera, Popovokapski Ezera, as well as the biggest and most famous lake group on the Balkan Peninsula – Sedemte Rilski Ezera (The 7 Rila Lakes). There are 10 tourist chalets and 2 high-mountain shelters built up in North-Western Rila.
South-Western Rila comprises 30% of the mountain - the lowest part with the average altitude above sea level of 1306.63 m. It is divided into two main ridges - northern, consisting of Mechi Vruh and Tsarev Vruh subpart and southern, divided into Parangal, Kapatnik and Hurs. Mt. Angel is the highest in this subpart (2643 m). Some of the more remarkable peaks here are Mt. Goliam Mechi (Big Bear) (2618 m), Mt. Uzunitsa (2606 m), Mt. Tsarev Vruh (Tsar’s Peak) (2378 m), Mt. Kapatnik (2170 m) and others. There are 2 tourist’s chalets in South-Western Rila. One of the oldest biosphere reserves in Bulgaria is located on the territory of this part - Parangalitsa, known also for its centuries-old spruces.
Some of the most well-known Bulgarian rivers flowing their waters in the direction of both the Black Sea and the Aegean Sea spring from Rila, i.e. the main watershed of the Balkans passes through it. Solely the Iskar River drains into the Black Sea, but its water catchment area in Rila is big enough including its initial tributaries Cherni (Black), Beli (White) and Levi (Left) Iskar as well as a lot of other smaller ones. The Chanakski Ezera (Chanak Lakes) in North-Western Rila are considered as the origin of the Iskar River near the cirque of the 7 Rila Lakes. The longest Bulgarian river - the Maritsa River as well as the Mesta River empty in the Aegean Sea, beyond the territory of Bulgaria. The first flows out of Marichini Ezera (Maritsa Lakes), south of Mt. Moussala, and the second drains the southern slopes of Eastern Rila. The water catchment area of Struma River (taking its rise from Vitosha Mountain) is spacious, too. It catches the waters of the western and south-western slopes of Rila and also empties into the Aegean Sea, on the territory of Greece. Among its Rila tributaries of greater importance are the Rila River, the Dzherman River, the Dupnitsa River and the Blagoevgrad Bistritsa River.
