Themain chain of the Alps, also called theAlpine divide is the central line of mountains that forms thedrainage divide of the range. Main chains ofmountain ranges are traditionally designated in this way, and generally include the highestpeaks of a range. TheAlps are something of an unusual case in that several significant groups of mountains are separated from the main chain by sizable distances. Among these groups are theDauphine Alps, the Eastern and WesternGraians, the entireBernese Alps, theTödi,Albula andSilvretta groups, theOrtler andAdamello ranges, and theDolomites ofVeneto andSouth Tyrol, as well as the lowerAlps ofVorarlberg, Bavaria, andSalzburg.

The Alpine Divide is defined for much of its distance by the watershed between the drainage basin of thePo in Italy on one side, with the other side of the divide being formed by theRhone, theRhine and theDanube. Further east, the watershed is between theAdige and theDanube, before heading into Austria and draining on both sides into the Danube. For much of its distance the watershed lies on or close to the Italian border, although there are numerous deviations, notably, the Swiss canton ofTicino which lies south of the range in the Po river basin.

For only a small portion of its total distance does the Alpine divide form a part of the mainEuropean watershed, in the central section where the watershed is between the Po and the Rhine.

The Alps are generally divided intoEastern Alps andWestern Alps, cut along a line betweenLake Como andLake Constance, following theRhine valley.^[1]

• The Eastern Alps (mainridge elongated and broad) belong toAustria,Germany,Italy,Slovenia, andSwitzerland.
• The Western Alps are higher, but their central chain is shorter and much curved; they are located inFrance, Italy, and Switzerland.

Piz Bernina (4,049 metres) is the highest peak of the Eastern Alps while the highest peak of the Western Alps isMont Blanc (4,810.45 metres).^[2]

From theMaloja Pass (1,815 m) the main watershed dips to the south-east for a short distance, and then runs eastwards and nearly over the highest summit of theBernina Range,Piz Bernina (4,049 m), to theBernina Pass. From here the main chain is less well defined, it rises toPiz Paradisin (3,302 m), beyond which it runs slightly north-east, east of the Italian resort ofLivigno, pastFraele Pass (1,952 m) and the source of theAdda, traversesPiz Murtarol (3,180 m) andMonte Forcola, where is the tripoint between the Danube, Po andAdige basins,^[3] then falls to theOfen Pass (2,149 m), soon heads north and rises once more inPiz Sesvenna (3,204 m).

TheReschen Pass (1,504 m) marks a break in the continuity of the Alpine chain. The deep valley, theVinschgau of the upper Adige, is one of the most remarkable features in the orography of the Alps. The littleReschen Lake, which forms the chief source of the Adige, is only 4 metres below the Pass, and 8 km from theInn valley. Eastward of this pass, the main chain runs north-east to theBrenner Pass along the snowy crest of theÖtztal, the highest point being theWeißkugel (3,739 m), then crossing theTimmelsjoch (2,474 m) and rising again inStubai Alps Both the highest summits of the Ötztal and the Stubai, theWildspitze (3,774 m) and theZuckerhütl (3,505 m), stand a little to the north.

TheBrenner (1,370 m) is the lowest of all the great road passes across the core part of the main chain and has always been the chief means of communication between Germany and Italy. For some way beyond it, the watershed runs eastwards over the highest crest of theZillertal Alps, which attains 3,510 metres in theHochfeiler. But, a little farther, at theDreiherrnspitze (3,499 m), the chain splits: the main watershed between the Black Sea and the Mediterranean heads south, along theRieserferner Group to theDolomites, andJulian Alps.

The main alpine divide head east, traversing theHigh Tauern range, crossing theGrossvenediger (3,666 m), passing just north of Austria's highest peak (theGrossglockner), traversingAnkogel (3,252 m), before curving northern across theLower Tauern, traversing its highest peak,Hochgolling (2,863 m) in theSchladming Tauern and then continuing on the same eastward path up to theSchober Pass inStyria. Thedrainage divide further runs eastwards through theNorthern Limestone Alps, ending at "Vienna Gate", the steep slopes of theLeopoldsberg (425 m) high above theDanube water gap and theVienna Basin.

Starting from theBocchetta di Altare or diColle di Cadibona (west ofSavona), the main chain extends first south-west, then north-west to theCol de Tenda, though nowhere rising much beyond the zone of coniferous trees. Beyond theCol de Tenda the direction is first roughly west, then north-west to theRocca dei Tre Vescovi (2,840 m), just south of theEnciastraia (2,955 m), several peaks of about 3,000 metres rising on thewatershed, though the highest of all, thePunta dell'Argentera (3,297 m) stands a little way to its north. From the Rocher des Trois Eveques the drainage divide runs due north for a long distance, though of the two loftiest peaks of this region one, theAiguille de Chambeyron (3,412 m), is just to the west, and the other, theMonviso (3,841 m), is just to the east of the divide. From the head of theVal Pellice the main chain runs north-west and diminishes much in average height until it reaches theMont Thabor (3,178 m), which forms the apex of a salient angle which the main chain here presents towards the west. From here the divide extends eastwards, culminating in theAiguille de Scolette (3,505 m), but makes a great curve to the north-west and back to the south-east before rising in theRocciamelone (3,509 m). From there the direction taken is north as far as the eastern summit (3,619 m) of theLevanna, the divide rising in a series of snowy peaks, though the loftiest point of the region, thePointe de Charbonnel (3,760 m), stands a little to the west. Once more the chain bends to the north-west, rising in several lofty peaks (the highest is theAiguille de la Grande Sassière, 3,751 m), before attaining the considerable depression of theLittle St Bernard Pass.

The divide then briefly turns north to theCol de la Soigne, and then north-east along the crest of the Mont Blanc chain, which culminates in the peak ofMont Blanc (4,810 m),^[2] the highest in the Alps. A number of high peaks line the divide, notably theGrandes Jorasses (4,208 m) before it reachesMont Dolent (3,823 m), where France, Italy and Switzerland meet. From there, after a short dip to the south-east, the chain takes, near theGreat St. Bernard Pass, a generally eastern direction that it maintains until it reachesMonte Rosa, where it bends northwards, making one small dip to the east to theSimplon Pass. It is in the portion of the watershed between the Grande St Bernard Pass and the Simplon that the main chain maintains a greater average height than in any other part. But, though it rises in a number of lofty peaks, such as theMont Vélan (3,727 m), theMatterhorn (4,478 m), theLyskamm (4,533 m), the Nord End ofMonte Rosa (4,575 m), and theWeissmies (4,023 m), many of the highest points of the region, such as theGrand Combin (4,314 m), theDent Blanche (4,357 m), theWeisshorn (4,505 m), the true summit orDufourspitze (4,634 m) of Monte Rosa itself, and theDom (4,545 m), all rise on its northern slope and not on the main chain. On the other hand, the chain between the Grande St Bernard and the Simplon sinks at barely half a dozen points below a level of 3,000 metres.

TheSimplon Pass (1.994 m) corresponds to a change in the main chain: the peaks and passes are lower, but as far as the Splugenpass, all the highest summits rise on the divide. From there to theSt. Gotthard pass (2,106 m) the divide runs north-east, crossingMonte Leone (3,533 m), andPizzo Rotondo (3,192 m). Near theWitenwasserenstock is the point where the basin of the Po, the Rhine and the Rhone meet, and the European Watershed joins the Alpine divide. From the St. Gotthard to theMaloja the watershed between the basins of theRhine andPo runs in a generally easterly direction. It goes overPasso del Lucomagno (1,915 m), acrossScopi (3,200 m),Piz Medel (3,210 m) andPiz Terri (3,149 m), where it turns towards the south to theRheinwaldhorn (3,402 m). Here the divide veers back east over theVogelberg (3,220 m) to the San Bernardino Pass (2,067 m), then over thePizzo Tambo (3,279 m), theSplugenpass (2,114 m) andPiz Timun (3,209 m). From here the divide heads south again toPizzo Stella (3,163 m) and then east overPizz Gallagiun (3,107 m), to where, near theLunghin pass, it reaches the main triple divide of the Alps: where water can flow to the Atlantic, the Mediterranean or the Black Sea. The mainEuropean watershed leaves the Alpine divide here, heading north, while the divide continues east to theMaloja Pass (1,815 m).

The main chain has moreglaciers and eternal snow than the independent or externalranges. The longest of these were both 14.9 kilometres (9+1⁄4 miles) a century ago, theMer de Glace atChamonix (now7.6 km or4+3⁄4 mi) and theGorner Glacier atZermatt (now12.5 km or7+3⁄4 mi). In theEastern Alps the longest glacier was thePasterze Glacier (8.4 km or5+1⁄4 mi in 1911), which is not near the true main watershed, though it clings to the slope of theGrossglockner (3,798 m) in the Hohe Tauern range east of the Dreiherrenspitze. But two other long glaciers in the Eastern Alps (theHintereis, and theGepatsch) are both in the Ötztal Alps, and so are close to the true mainwatershed.

• Alps
  • Eastern Alps
  • Western Alps
• Geography of the Alps
• High Alps

  This article incorporates text from a publication now in thepublic domain: Lake, Philip; Knox, Howard;Coolidge, W. A. B. (1911). "Alps". InChisholm, Hugh (ed.).Encyclopædia Britannica. Vol. 1 (11th ed.). Cambridge University Press. pp. 737–754.

• Simplified depiction of the Alpine divide onGeoFinder.ch