A wage is meant to help someone support themselves. The location you live can have a large effect on the cost of living in that area. Desirable areas - such as New York City and the coast line - can have higher prices because everyone wants to live there. Where you live can also influence how much food costs; if you live closer to the sea or a big export/import area, food can be cheaper. If you live further away, food might be more expensive to make up for more transportation-related costs.
With all of that in mind, an entry level job in New York City will probably pay more than an entry level job in rural Kentucky because the cost of living is higher in New York City.
What you earn and where you live are closely involved with geography. If you have highly populated areas that are far from natural resources, the cost of feeding, transporting and meeting their needs costs much more. This is truest of highly populated areas far from the sea.
Location and climate have large effects on income levels and income growth through their effects on transport costs, disease burdens, and agricultural productivity. A geographical area needs to have natural resources that are sufficient to provide for its population.