The Italian lakes, measured

The six large Italian lakes are not variations on one thing: Garda covers 369.98¹ sq km at up to 346¹ m deep, Como reaches 410⁵ m, and Trasimeno spreads over 124¹⁰ to 128¹⁰ sq km at a maximum depth of 6 m, which changes what you can do on each of them.

The six, in surface and depth

Garda is the largest at 369.98¹ sq km (142.8 square miles), 51.6 km¹ long, 17.2 km¹ at its widest, with 158.4 km¹ of shoreline and 49 cubic kilometers of water at 65 m above sea level. Maggiore follows at 212.5³ sq km, 370³ m deep, 37.5³ cubic kilometers, second in Italy on both surface and volume.

Como covers 145⁵ sq km and drops to 410⁵ m, with a mean depth of 155⁵ m and 170 km⁵ of a very indented shore. Bolsena covers 114.53⁸ sq km at 151⁸ m deep, Iseo 61 sq km at 251⁶ m, and Trasimeno 124¹⁰ to 128¹⁰ sq km at 3 to 6 m.

Where the sources disagree, and by how much

Garda's maximum depth is 346¹ m according to the Comunità del Garda, the body of the lakeside municipalities, and 350¹ m in the 2004 OLL report produced by the region of Lombardy with ARPA and CNR-IRSA. The difference has not been resolved, and this page carries both rather than picking one.

Iseo has the same problem on surface: the institutional source says 61 sq km, popular sources say 65.3⁷. Trasimeno's own regional authority publishes 128¹⁰ sq km on one page and 124¹⁰ in a document by the same office, and the level of Maggiore and of Trasimeno above sea level is not published at all by the sources we read.

Volcanic, glacial, and shallow: three different lakes

Bolsena sits in a caldera of the Vulsini volcanic complex, 305⁸ m above sea level, and the regional water plan calls it the largest lake in the world formed in an extinct volcanic crater, a claim carried by that source alone. It holds two islands, Bisentina and Martana, and is the fifth Italian lake by area.

Iseo is pseudomeromictic: it mixes completely only rarely, which is why its deep water has an oxygen problem that shallow Trasimeno does not. Maggiore drains a basin of 6,599⁴ sq km split between Italy at 3,229⁴ and Switzerland at 3,370⁴, though 80% of the water surface is Italian, and its level is regulated by the Miorina dam at Sesto Calende.

What the water is like

Garda's surface runs 43 to 50°F (6 to 10°C) in winter and 75 to 90°F (24 to 32°C) from June to August, warmer than any of the others in summer because of its volume and shape. Five islands sit in it, and the largest, Isola del Garda, is private.

Depth is what decides the rest. A lake 410⁵ m deep like Como never really warms; one 6 m deep like Trasimeno warms through, which makes it a different swim and a different fishery.

The lakes are a foreign market, not a domestic one

Foreign visitors take 82.2%¹² of the nights spent at the Italian lakes, the highest share of any product commonly filed as domestic, against 54.8%¹² for farm stays and 50.3%¹² for small towns. Only spas stay domestic, at 64.6%¹² Italian nights.

That number decides what the shoreline sells and in which languages. Region pages cover the surrounding areas: Lombardy, Veneto, Piedmont, Umbria and Lazio.

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