This man-made reservoir is located in the northernmost state of Perlis. Stretching over 1,300 hectares, Timah Tasoh Lake was first established in 1987 and completed in 1992, and currently acts as a water catchment area for its surroundings. The name Timah Tasoh was derived by combining the names of the two rivers that flow into the lake, Sungai Timah and Sungai Tasoh.