Lake Orta, also called Lake Cusio, is entirely situated in Piedmont in the Province of Novara. It is the most westerly of the Prealpine lakes, with a surface area of about 18 sq.km, and lies on a north-south line, in the same direction as the lower part of Lake Maggiore from which it is separated by the Mottarone range. Its geology is interesting because its outlet river, the Nigoglia, flows north, instead of to the south as is usual, and runs into the River Strona, which then divides into two tributaries of Lake Maggiore. The little, elliptical island of San Giulio sits almost in the middle of the lake. The banks of the lake are covered with woods and country houses with lovely gardens, and there are also a number of little health resorts built on terraces or facing the lake. The most visited place is Orta San Giulio and Omegna is the most important industrial town. A road runs all the way round the lake.