The populated area today known as Hillsdale took form in the mid-to-late 19th century as land speculators, led by David P. Patterson, developed subdivisons to profit from the coming of the Hackensack and New York Railroad (later New Jersey and New York Railroad).
Gap is a census-designated place and town in Salisbury Township, Lancaster County, Pennsylvania with a zip code of 17527. The population was 1,611 at the 2000 census. It is the terminus for four Pennsylvania highways: 772, 741, 897, and the heavily-used 41, which goes toward Wilmington, DE. Gap has a history which can be dated as far back as William Penn's first visits to the area.
A mountain pass (also called a gap, saddle, or col) is a passage over a mountain range. They typically occur in valleys between mountain ridges, in low points along mountain watersheds or just the lowest point on a mountain ridge between two peaks. They can be relatively short in length (the width of a ridge) or they can be valleys many miles long. Mountain passes are often the location where roads and railways are built to get through the mountains. Many of them have become famous throughout history for their importance in trade and commerce.