In relation to European rivers, Italy does not have large watercourses in terms of length, this is because the country is closed to the north by the Alps and never has a large extension; the Po still crosses it from west to east for a good part of its largest portion, including the Po Valley.Almost all the major Italian watercourses flow entirely in the country, the only exception being the Ticino which originates in Switzerland; between the fourth and the seventh place we find only tributaries of the Po.
Among the rivers that have only a short stretch in the Italian peninsula we have the Isonzo in its final section and the Drava which with 749 km, of which only the initial 10 in South Tyrol, is the longest river to interest the Italian territory.
| River | Length (km) | Length (mi) | Mouth | Regions |
| Drava (1) | 749 km | 465 mi | Danube | Trentino-South Tyrol |
| Po (2) | 652 km | 405 mi | Adriatic Sea | Piedmont, Lombardy, Emilia-Romagna, Veneto |
| Adige | 410 km | 255 mi | Adriatic Sea | Trentino-South Tyrol, Veneto |
| Tiber (3) | 405 km | 252 mi | Tyrrhenian Sea | Emilia-Romagna, Tuscany, Umbria, Lazio |
| Adda | 313 km | 194 mi | Po | Lombardy |
| Oglio | 280 km | 174 mi | Po | Lombardy |
| Tànaro (4) | 276 km | 171 mi | Po | Liguria, Piedmont, Lombardy |
| Ticino (5) | 248 km | 154 mi | Po | Switzerland, Piedmont, Lombardy |
| Arno | 241 km | 150 mi | Ligurian Sea | Tuscany |
| Piave | 231 km | 144 mi | Adriatic Sea | Friuli-Venezia Giulia, Veneto |
| Reno | 211 km | 131 mi | Adriatic Sea | Tuscany, Emilia-Romagna |
| Sarca-Mincio (6) | 194 km | 121 mi | Po | Trentino-South Tyrol, Veneto, Lombardy |
| Volturno | 175 km | 109 mi | Tyrrhenian Sea | Molise, Campania |
| Brenta | 174 km | 108 mi | Adriatic Sea | Trentino-South Tyrol, Veneto |
| Secchia | 172 km | 107 mi | Po | Emilia-Romagna, Lombardy |
| Ofanto | 170 km | 106 mi | Adriatic Sea | Campania, Basilicata, Apulia |
| Tagliamento | 170 km | 106 mi | Adriatic Sea | Veneto, Friuli-Venezia Giulia |
| Dora Baltea | 168 km | 104 mi | Po | Aosta Valley, Piedmont |
| Chiese | 160 km | 99 mi | Oglio | Trentino-South Tyrol, Lombardy |
| Ombrone | 160 km | 99 mi | Tyrrhenian Sea | Tuscany |
| Liri-Garigliano (7) | 158 km | 98 mi | Tyrrhenian Sea | Abruzzo, Lazio, Campania |
| Bòrmida | 153 km | 95 mi | Tanaro | Liguria, Piedmont |
| Tirso (8) | 152 km | 94 mi | Sea of Sardinia | Sardinia |
| Basento | 149 km | 93 mi | Ionian Sea | Basilicata |
| Panaro | 148 km | 92 mi | Po | Emilia-Romagna |
| Aterno-Pescara | 145 km | 90 mi | Adriatic Sea | Abruzzo |
(1) Only the first 10 kilometers are in Italy, the rest of the course develops between Austria, Slovenia, Croatia and Hungary.
(2) It is by far also the river with the greatest flow.
(3) Mussolini changed the borders between Emilia-Romagna and Tuscany to move the source of the river in his region.
(4) It would be the longest river in Italy (712 km) if ancient geographers had considered the Po as its tributary.
(5) The source is in Switzerland, like the first 104 km of its course, the second Italian river for water flow.
(6) It is called Sarca in the Trentino section, it comes out of Lake Garda with the name of Mincio.
(7) It takes the name Garigliano in the last stretch at the confluence of the Liri with the Gari.
(8) Longest river on an Italian island.