[2][1][5] Several of its early tributaries flow off the north side of Pine Mountain into it, one of the principal ones being Cowan Creek.

[citation needed] The discharge rate at Hazard varies seasonally, being high in the winter and spring and low in the summer and autumn.

[1] This is brought about by higher rainfall during the first half of the calendar year, and regularly causes floods in the spring.

[1] Half of one percent of the area of the North Fork Kentucky River basin has been disturbed by mining.

[7][6] Three quarters of the sediment load is deposited between Jackson and Heidelberg, estimated by the USGS and KGS to be mostly just upstream of the latter.

[8] Because of the mining, the North Fork is also one of the three major sources of dissolved solids in the Kentucky River system.

[21] The North Fork was the location of seven species of freshwater mussels as of 1975, and their habitat had suffered from significant reduction since the start of the 20th century.