Cassop is a village and former civil parish, now in the parish of Cassop-cum-Quarrington, in the County Durham district, in the ceremonial county of Durham, England. It has a population of about 500 and is located near the city of Durham. A former mining village, mining is no longer the main occupation of Cassop's inhabitants due to extensive mine closure ov…Cassop is a village and former civil parish, now in the parish of Cassop-cum-Quarrington, in the County Durham district, in the ceremonial county of Durham, England. It has a population of about 500 and is located near the city of Durham. A former mining village, mining is no longer the main occupation of Cassop's inhabitants due to extensive mine closure over the last 30 years.