Lake Coghinas (Italian: Lago di Coghinas) is an artificial lake, in northern Sardinia, Italy, located between the provinces of Sassari and Olbia-Tempio. With a surface of 17.8 km² and a capacity of 254 millions cubic metres of water, it is the second largest lake in the region (second only to Lake Omodeo) and one of the major reservoirs in Italy.