Hammersley Fork

Hammersley Fork
Hammersley Fork
Mouth Location of the mouth of Hammersely Fork in Pennsylvania
Other name(s)	Hammersley Fork Creek
Etymology	named after J.P. Hammersley
Basin features
Main source	central Eulalia Township, Potter County, Pennsylvania between 1,800 and 1,820 feet (549 and 555 m)
River mouth	Kettle Creek in Leidy Township, Clinton County, Pennsylvania 968 ft (295 m) 41°26′50″N 77°52′11″W / 41.4471°N 77.8698°W / 41.4471; -77.8698Coordinates: 41°26′50″N 77°52′11″W / 41.4471°N 77.8698°W / 41.4471; -77.8698
Progression	Kettle Creek → West Branch Susquehanna River → Susquehanna River → Chesapeake Bay
Basin size	32.55 sq mi (84.3 km2)
Physical characteristics
Length	10.0 mi (16.1 km)

Hammersley Fork (also known as Hammersley Fork Creek) is a tributary of Kettle Creek in Potter County and Clinton County, Pennsylvania, in the United States. It is approximately 10.0 miles (16.1 km) long and flows through Warton Township in Potter County and Leidy Township in Clinton County. The watershed of the stream has an area of 32.7 square miles (85 km²). The main rock formation in the watershed is the Pottsville Formation. A number of bridges cross the stream.

There are no state roads and virtually no township roads in the watershed of Hammersley Fork. However, there are dirt roads and gravel roads, and several stream crossings in the watershed. The first settlers arrived in the watershed in 1827 and the first roads in the area were constructed several years later. Industrial activities such as logging were common in the watershed in the early 20th century, but there is currently virtually no such activity there. Wild trout naturally reproduce in the stream throughout its entire length. Most of the creek has a substantial riparian buffer.

Hammersley Fork begins in central Eulalia Township, Potter County, near the Sinnemahoning Creek watershed. It flows southeast to Elk Lick Knob, where it receives the tributary Black Mark Hollow. The stream then turns south and flows into a valley, passing Bunnell Ridge. The valley gets deeper and the stream receives several small tributaries. It turns southwest shortly downstream of the mouth of Elkhorn Run. In the southern reaches of the township, the stream receives the tributary Bell Branch and turns south-southeast, exiting Eulalia Township.

Upon leaving Eulalia Township, Potter County, Hammersley Fork enters Leidy Township, Clinton County and continues south, passing by Susquehannock State Forest. The stream continues south for some distance and crosses Pennsylvania Route 144. Immediately after crossing Pennsylvania Route 144, the stream reaches its confluence with Kettle Creek. Hammersley Fork joins Kettle Creek 19.90 miles (32.03 km) upstream of its mouth.