Oglio

{{For|the record label|Oglio Records}}

{{Infobox river

| name = Oglio

| native_name = {{native name|lmo|Òi{{noitalics| / }}Ùi}}

| image = Soncino Orzinuovi ponte Oglio.JPG

| image_caption = The river between Soncino and Orzinuovi

| map = Oglio.png

| map_size = 250px

| map_caption = Course of the river Oglio

| subdivision_type1 = country

| subdivision_name1 = Italy

| subdivision_type2 = region

| subdivision_name2 = Lombardy

| subdivision_type3 = provinces

| subdivision_name3 = Brescia, Bergamo, Cremona, Mantua

| source1 = Valle delle Messi, as Frigidolfo branch

| source1_location = near Punta Valmalza, Sobretta-Gavia Group, Ortler Alps, Lombardy

| source1_elevation = {{convert|3035|m|ft|abbr=on}}

| source1_coordinates= {{coord|46|20|31.5|N|10|27|03.5|E}}

| source2 = Lake Ercavallo, Valle di Viso, as Arcanello branch

| source2_location = at the slopes of Cima di Caione, Ortler Alps, Lombardy

| source2_elevation = {{convert|2621|m|ft|abbr=on}}

| source2_coordinates= {{coord|46|20|21.1|N|10|31|35.5|E}}

| source3 = Lake Pisgana, as Narcanello branch

| source3_location = Narcanello Valley, near Vedretta di Pisgana, Presena glacier, Adamello-Presanella Alps, Lombardy

| source3_elevation = {{convert|2500|m|ft|abbr=on}}

| source3_coordinates= {{coord|46|12|22|N|10|31|49|E}}

| source4 = Ogliolo branch

| source4_location = Corteno Valley, on the provincial border between Corteno Golgi, province of Brescia and Aprica, province of Sondrio, Lombardy, near Zappello dell'Asino

| source4_elevation = {{convert|1172|m|ft|abbr=on}}

| source4_coordinates= {{coord|46|08|52|N|10|09|54.2|E}}

| source_confluence = confluence of Frigidolfo and Narcanello branches

| source_confluence_location = Ponte di Legno, province of Brescia, Lombardy

| source_confluence_elevation = {{convert|1253|m|ft|abbr=on}}

| source_confluence_coordinates= {{coord|46|15|32.7|N|10|30|28.7|E}}

| mouth = Po

| mouth_location = at the municipal border between Marcaria and Viadana, province of Mantua, Lombardy

| mouth_coordinates = {{coord|45|02|40|N|10|39|37|E|display=it}}

| progression = {{RPo}}

| length = {{convert|280|km|mi|abbr=on}}

| discharge1_avg = {{convert|137|m3/s|cuft/s|abbr=on}}

| basin_size = {{convert|6649|km2|mi2|abbr=on}}

}}

File:Nascita del fiume Oglio - Ponte di Legno.jpg branch (left) and the Narcanello branch (right), Ponte di Legno]]File:Fiume Oglio verso sud - Forno d'Allione - Berzo Demo (Foto Luca Giarelli).jpg, Val Camonica]]

The Oglio ({{IPA|it|ˈɔʎʎo|lang}}; {{langx|la|Ollius}} or {{lang|la|Olius}}; {{langx|lmo|Òi}}, {{langx|lmo|label=Cremonese|Ùi}}) is a left-side tributary of the river Po in Lombardy, Italy. It is {{convert|280|km|mi}} long.

In the hierarchy of the Po's tributaries, with its {{convert|280|km|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).

Overview

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 {{convert|1.5|m3/s|cuft/s|abbr=on}}.

The Frigidolfo branch, before merging with Narcanello branch, receives the Arcanello branch, which have an average discharge of {{convert|0.5|m3/s|cuft/s|abbr=on}}, which receives a minor branch originating from Lake Ercavallo.

The Ogliolo stream, with an average discharge of {{convert|2.5|m3/s|cuft/s|abbr=on}} and a length of {{convert|20|km|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.{{Cn|date=January 2025}}

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 {{convert|6649|km2|mi2}}. It is part of the larger Po-Adige basin.{{Cn|date=January 2025}}

The course of the river main branch

=[[Val Camonica|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 {{coord|45|51|38.2|N|10|08|56|E}}, on the border between Artogne, Brescia and Rogno, Bergamo.

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

:* Budrio stream, at Erbanno, Darfo Boario Terme {{coord|45|53|56.1|N|10|12|00.5|E}}

:* Gleno, at the triple municipal border between Vilminore di Scalve, Colere and Azzone

=[[Lake Iseo]] section=

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

width="958" class="wikitable" style="margin-left: auto; margin-right: auto; border: none;"

|+The tributaries of the Iseo lake

style="font-weight:bold;color:#555;"

! Brescia side:

! Bergamo side:

valign="top" |

| valign="top" |

=[[Po Valley]] section=

The Oglio main branch leaves the lake at the provincial border between Sarnico, Bergamo and Paratico, Brescia {{coord|45|39|56.5|N|09|57|24|E}} and begins to follow (approximately) this provincial border.

At the triple provincial border between Torre Pallavicina (Bergamo), Roccafranca (Brescia) and Soncino (Cremona) {{coord|45|25|40.5|N|09|53|07.5|E}} 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) {{coord|45|07|57|N|10|29|32|E}} where the river enters entirely in the Mantua province.

At the municipal border between Marcaria and Viadana {{coord|45|02|40|N|10|39|37|E}}, the Oglio river enters the Po river.