<P> Bear Lake is a natural freshwater lake on the Utah - Idaho border in the Western United States . About 109 square miles ( 280 km ) in size , it is split about equally between the two states ; its Utah portion comprises the second - largest natural freshwater lake in Utah , after Utah Lake . The lake has been called the `` Caribbean of the Rockies '' for its unique turquoise - blue color , which is due to the reflection of calcium carbonate ( limestone ) deposits suspended in the lake . Its water properties have led to the evolution of several unique species of fauna that occur only within the lake . Bear Lake is over 250,000 years old . It was formed by fault subsidence that continues today , slowly deepening the lake along the eastern side . </P>
<P> Bear Lake is a natural freshwater lake on the Utah - Idaho border in the Western United States . About 109 square miles ( 280 km ) in size , it is split about equally between the two states ; its Utah portion comprises the second - largest natural freshwater lake in Utah , after Utah Lake . The lake has been called the `` Caribbean of the Rockies '' for its unique turquoise - blue color , which is due to the reflection of calcium carbonate ( limestone ) deposits suspended in the lake . Its water properties have led to the evolution of several unique species of fauna that occur only within the lake . Bear Lake is over 250,000 years old . It was formed by fault subsidence that continues today , slowly deepening the lake along the eastern side . </P>
what is the surface area of bear lake
what is the surface area of bear lake
109 square miles ( 280 km )
109 square miles ( 280 km )