The river between Soncino and Orzinuovi
Course of the river Oglio
Native nameÒi / Ùi (Lombard)
provincesBrescia, Bergamo, Cremona, Mantua
Physical characteristics
SourceValle delle Messi, as Frigidolfo branch
 • locationnear Punta Valmalza, Sobretta-Gavia Group, Ortler Alps, Lombardy
 • coordinates46°20′31.5″N 10°27′03.5″E / 46.342083°N 10.450972°E / 46.342083; 10.450972
 • elevation3,035 m (9,957 ft)
2nd sourceLake Ercavallo, Valle di Viso, as Arcanello branch
 • locationat the slopes of Cima di Caione, Ortler Alps, Lombardy
 • coordinates46°20′21.1″N 10°31′35.5″E / 46.339194°N 10.526528°E / 46.339194; 10.526528
 • elevation2,621 m (8,599 ft)
3rd sourceLake Pisgana, as Narcanello branch
 • locationNarcanello Valley, near Vedretta di Pisgana, Presena glacier, Adamello-Presanella Alps, Lombardy
 • coordinates46°12′22″N 10°31′49″E / 46.20611°N 10.53028°E / 46.20611; 10.53028
 • elevation2,500 m (8,200 ft)
4th sourceOgliolo branch
 • locationCorteno Valley, on the provincial border between Corteno Golgi, province of Brescia and Aprica, province of Sondrio, Lombardy, near Zappello dell'Asino
 • coordinates46°08′52″N 10°09′54.2″E / 46.14778°N 10.165056°E / 46.14778; 10.165056
 • elevation1,172 m (3,845 ft)
Source confluenceconfluence of Frigidolfo and Narcanello branches
 • locationPonte di Legno, province of Brescia, Lombardy
 • coordinates46°15′32.7″N 10°30′28.7″E / 46.259083°N 10.507972°E / 46.259083; 10.507972
 • elevation1,253 m (4,111 ft)
 • location
at the municipal border between Marcaria and Viadana, province of Mantua, Lombardy
 • coordinates
45°02′40″N 10°39′37″E / 45.04444°N 10.66028°E / 45.04444; 10.66028
Length280 km (170 mi)
Basin size6,649 km2 (2,567 sq mi)
 • average137 m3/s (4,800 cu ft/s)
Basin features
ProgressionPoAdriatic Sea
View of the confluence of the Frigidolfo branch (left) and the Narcanello branch (right), Ponte di Legno
River Oglio at Berzo Demo, Val Camonica

The Oglio (Italian: [ˈɔʎʎo]; Latin: Ollius or Olius; Lombard: Òi, Cremonese: Ùi) is a left-side tributary of the river Po in Lombardy, Italy. It is 280 kilometres (170 mi) long. In the hierarchy of the Po's tributaries, with its 280 kilometres (170 mi) of length, it occupies the 2nd place per length (after the river Adda), while it is the 4th per basin surface (after Tanaro, Adda and Ticino), and the 3rd per average discharge at the mouth (after Ticino and Adda).


The Oglio is formed from the confluence of two mountain streams, the Narcanello branch from the Presena Glacier, in the Adamello group and the Frigidolfo branch, in the Corno dei Tre Signori, part of the Stelvio National Park. The streams merge near Pezzo di Ponte di Legno, both the streams have an average discharge of 1.5 m3/s (53 cu ft/s). The Frigidolfo branch, before merging with Narcanello branch, receives the Arcanello branch, which have an average discharge of 0.5 m3/s (18 cu ft/s), which receives a minor branch originating from Lake Ercavallo. The Ogliolo stream, with an average discharge of 2.5 m3/s (88 cu ft/s) and a length of 20 kilometres (12 mi) (similar to the length of the main branch between the Frigidolfo-Narcanello merge at Ponte Di Legno and the Oglio-Ogliolo merge at Edolo) is sometimes considered as a de facto fourth branch of the Oglio river.

It flows in a southwest direction, through Valcamonica and enters into the Lake Iseo at Costa Volpino. It leaves Lake Iseo at Sarnico and, after traveling a zone of moraine deposits, it joins the Po river at Torredoglio, not far from Cesole and Scorzarolo, in the province of Mantua. Its drainage basin, which corresponds to the region of Valle Camonica, covers 6,649 square kilometres (2,567 sq mi). It is part of the larger Po-Adige basin.

The course of the river main branch

Camonica Valley section

The river in the Camonica Valley flows almost exclusively in the province of Brescia, entering in the province of Bergamo only at 45°51′38.2″N 10°08′56″E / 45.860611°N 10.14889°E / 45.860611; 10.14889, on the border between Artogne, Brescia and Rogno, Bergamo.

The following is a list (incomplete) of the tributaries in the Camonica Valley:

Lake Iseo section

At Costa Volpino, the Oglio river enters the Iseo lake with a mixed delta-estuary mouth.

The tributaries of the Iseo lake
Brescia side: Bergamo side:

Po Valley section

The Oglio main branch leaves the lake at the provincial border between Sarnico, Bergamo and Paratico, Brescia 45°39′56.5″N 09°57′24″E / 45.665694°N 9.95667°E / 45.665694; 9.95667 and begins to follow (approximately) this provincial border. At the triple provincial border between Torre Pallavicina (Bergamo), Roccafranca (Brescia) and Soncino (Cremona) 45°25′40.5″N 09°53′07.5″E / 45.427917°N 9.885417°E / 45.427917; 9.885417 the Oglio begins to follow (approximately) the provincial border between the Brescia-Cremona provincial border.

The major tributaries in the Po valley are the following:

At this triple provincial border the Oglio river begins following the Mantua-Cremona provincial border, which leaves at the triple municipal border between Acquanegra sul Chiese (Mantua), Calvatone (Cremona) and Bozzolo (Mantua) 45°07′57″N 10°29′32″E / 45.13250°N 10.49222°E / 45.13250; 10.49222 where the river enters entirely in the Mantua province.

At the municipal border between Marcaria and Viadana 45°02′40″N 10°39′37″E / 45.04444°N 10.66028°E / 45.04444; 10.66028, the Oglio river enters the Po river.