One of the most distinct features of New York City is it ordered network of streets. This organized layout is a dramatic difference from other older cities in the United States and even medieval cities in Europe. The mesh-like pattern was no accident; it was a result of The Commissioners’ Plan of 1811.
According to Wikipedia, the plan called for a regular grid of streets and property lines without regard to the topography of the island itself. The plan called for sixteen numbered and lettered avenues running north and south roughly parallel to the shore of the Hudson River. Except in the north and south ends of the island, the avenues would begin with First Avenue on the east side and run through Twelfth Avenue in the west. To the east of 1st Avenue, there would be four additional lettered avenues running from Avenue A eastward to Avenue D. Furthermore, there would also be 155 orthogonal cross streets. The location of the cross streets was fixed at the boundaries of 5-acre parcels into which the land had previously been divided.