The Sinyaya (Russian: Синяя; Yakut: Сиинэ, Siine) is a river in the Sakha Republic, Russia.

[1] The river begins in the Tampa-Ottoowo, a small lake located in the Lena Plateau at an elevation of 278 metres (912 ft).

In its lower course the river is flanked by picturesque rock formations, the Sinyaya Pillars.

The Sinyaya meets the left bank of the Lena near Sinsk, 150 km (93 mi) upstream from Yakutsk and 1,716 km (1,066 mi) from the Lena's mouth.

The river flows across three districts, Verkhnevilyuy, Gorny and Khangalassky.