Sidneys Knob is unique in that is an atypical mountain

Mountain

Image:Himalaya_annotated.jpg|thumb|right|The Himalayan mountain range with Mount Everestrect 58 14 160 49 Chomo Lonzorect 200 28 335 52 Makalurect 378 24 566 45 Mount Everestrect 188 581 920 656 Tibetan Plateaurect 250 406 340 427 Rong River...

 for Pennsylvania. Most of the mountains in the Commonwealth

Commonwealth

Commonwealth is a traditional English term for a political community founded for the common good. Historically, it has sometimes been synonymous with "republic."More recently it has been used for fraternal associations of some sovereign nations...

 are long linear ridges or flatted topped plateau

Plateau

In geology and earth science, a plateau , also called a high plain or tableland, is an area of highland, usually consisting of relatively flat terrain. A highly eroded plateau is called a dissected plateau...

 mountains. Sidneys Knob is conical in shape and besides Gillespie Point in the northern part of Pennsylvania, the only one of its kind. This "knob" is the cultimation of Cove Mountain and Scrub Ridge.

The mountain is seen on postcards, mainly viewed from the Pennsylvania Turnpike

Pennsylvania Turnpike

The Pennsylvania Turnpike is a toll highway system operated by the Pennsylvania Turnpike Commission in the Commonwealth of Pennsylvania, United States. The three sections of the turnpike system total . The main section extends from Ohio to New Jersey and is long...

, as vehicles exit out of the Tuscarora Mountain Tunnel

Tuscarora Mountain Tunnel

Tuscarora Mountain Tunnel is one of four original Pennsylvania Turnpike tunnels still in active use. A second tube was bored in the late 1960s to ease traffic conditions. The Tuscarora Mountain tunnels measure 1.1 miles in length and are the second-longest active tunnels on the Pennsylvania...

. Sometimes referred to as "Pyramid Point" or on early postcards as Henry's Knob, this landmark is one of the most noted on the turnpike.