"Deep Notch" is sometimes used to refer to the entire section of Route 42 from Bushnellville at the county line to West Kill, where the road runs through the narrow valley of Bushnellville Creek between  3,520-foot (1,070 m) Halcott Mountain on the west and 3,540-foot (1,080 m) Mount Sherrill, both High Peaks of the range, to the east.
The actual notch is the roughly 1.5-mile (2.4 km) section north of the upper tributary of the creek to West Kill.
On the west is an unnamed 3,408-foot (1,039 m) peak known as Northeast Halcott or Sleeping Lion; to the west is a 3,280-foot (1,000 m) false summit of Balsam Mountain, itself a subpeak of Sherrill.

The two generally level summits are separated by roughly one mile (1.6 km).
Between them, the road crests at 1,900 feet (580 m) in the notch.
On the west, that leaves a slope that rises 1,400 feet (430 m) to where it levels off below the summit of Northeast Halcott in 2,000 horizontal feet (610 m), complemented by a 1,300-foot (400 m) rise over a similar distance on the east.
The grades are 70 percent and 65 percent respectively.

Both slopes are property of the state of New York, managed by the Department of Environmental Conservation as part of the Catskill Park Forest Preserve.
The western land is in the Halcott Mountain Wild Forest and the eastern property in the West Kill Wilderness Area.
As part of the Forest Preserve they remain forever wild, in accordance with the state constitution.
There is little development in the area save some houses along the road to the south.

South of the notch the land rises gently but steadily into it, gaining about 450 feet (140 m) over two miles (3 km) from Bushnellville.
To the north it descends more rapidly to the hamlet of West Kill.
The highway drops 525 feet (160 m) in a half-mile (1 km) to the junction with Greene County Route 6.

Route 42 is one of only three paved roads crossing gaps in a long chain of ranges that extends from Plattekill Mountain in the east to Utsayantha Mountain, near Stamford, in the west.
It allows residents of the areas of Ulster and Delaware counties to the south and southwest (such as Pine Hill, Fleischmanns and Margaretville, to get to places like Prattsville and Windham to the north without having to go a long distance out of their way.
In addition, it is the most common route to the rest of Greene County for residents of the Town of Halcott to the west, isolated from the rest of the county by mountains along its eastern and northern border.

All of Deep Notch is within the Hudson River watershed.
Bushnellville Creek drains into Esopus Creek to the south, and the north side feeds the West Kill, a Schoharie Creek tributary.
The Schoharie's waters ultimately reach the Hudson via a circuitous route ending with the Mohawk River.
"Deep Notch" is sometimes used to refer to the entire section of Route 42 from Bushnellville at the county line to West Kill, where the road runs through the narrow valley of Bushnellville Creek between  3,520-foot (1,070 m) Halcott Mountain on the west and 3,540-foot (1,080 m) Mount Sherrill, both High Peaks of the range, to the east. The actual notch is the roughly 1.5-mile (2.4 km) section north of the upper tributary of the creek to West Kill. On the west is an unnamed 3,408-foot (1,039 m) peak known as Northeast Halcott or Sleeping Lion; to the west is a 3,280-foot (1,000 m) false summit of Balsam Mountain, itself a subpeak of Sherrill.
The two generally level summits are separated by roughly one mile (1.6 km). Between them, the road crests at 1,900 feet (580 m) in the notch. On the west, that leaves a slope that rises 1,400 feet (430 m) to where it levels off below the summit of Northeast Halcott in 2,000 horizontal feet (610 m), complemented by a 1,300-foot (400 m) rise over a similar distance on the east. The grades are 70 percent and 65 percent respectively.
Both slopes are property of the state of New York, managed by the Department of Environmental Conservation as part of the Catskill Park Forest Preserve. The western land is in the Halcott Mountain Wild Forest and the eastern property in the West Kill Wilderness Area. As part of the Forest Preserve they remain forever wild, in accordance with the state constitution. There is little development in the area save some houses along the road to the south.
South of the notch the land rises gently but steadily into it, gaining about 450 feet (140 m) over two miles (3 km) from Bushnellville. To the north it descends more rapidly to the hamlet of West Kill. The highway drops 525 feet (160 m) in a half-mile (1 km) to the junction with Greene County Route 6.
Route 42 is one of only three paved roads crossing gaps in a long chain of ranges that extends from Plattekill Mountain in the east to Utsayantha Mountain, near Stamford, in the west. It allows residents of the areas of Ulster and Delaware counties to the south and southwest (such as Pine Hill, Fleischmanns and Margaretville, to get to places like Prattsville and Windham to the north without having to go a long distance out of their way. In addition, it is the most common route to the rest of Greene County for residents of the Town of Halcott to the west, isolated from the rest of the county by mountains along its eastern and northern border.
All of Deep Notch is within the Hudson River watershed. Bushnellville Creek drains into Esopus Creek to the south, and the north side feeds the West Kill, a Schoharie Creek tributary. The Schoharie's waters ultimately reach the Hudson via a circuitous route ending with the Mohawk River.
Deep Notch