Gangca County (Tibetan: རྐང་ཚ་རྫོང; Chinese: 刚察县) is a county of northeastern Qinghai province, China, on the northern shore of Qinghai Lake.

Gangca County is made up of 2 towns and 3 townships: With an elevation of around 3,300 metres (10,800 ft), Gangca County has an alpine subarctic climate (Köppen Dwc), with long, very cold, dry, and sunny winters, and short, rainy, mild summers.

Average low temperatures are below freezing from late September to mid May; however, due to the wide diurnal temperature variation, the average high is above freezing from March to November inclusive.

The monthly 24-hour average temperature ranges from −13.5 °C (7.7 °F) in January to 10.9 °C (51.6 °F) in July, while the annual mean is −0.32 °C (31.4 °F).

Over 80% of the annual precipitation of 379 mm (14.9 in) is delivered from June to September.