Gridded to the max?

Which US city today is most covered by a single grid? Street grids have always had a special role in US cities. William Penn gave us our first planned grid for Philadelphia, complete with four squares towards the corners and a large one in the middle. Philadlephia is sort of the anti-Boston of colonial times; Philly's cow paths never led to streets. Manhattan used Philadelphia's example to give us our most famous grid that runs north from city hall in Lower Manhattan to clear past the upper reaches of Central Park. It is impossible to imagine the growth and developoment of New York without the democratizing effect of the grid. Even today, it may be the grid in purest form. Broadway alone of major streets runs on an angle in the lower 2/3's of the island. I suspect my own city of Chicago is the most gridded of all. First the city is incredibly large and second virtually every part of it is part of the grid (with the exception of a few fringe neighborhoods. Chicago's grid may not be as pure as Manhattan (angular streets leave the downtown area in most directions, many Indian trails from days past). But it more than makes up for the lack of purity through its gigantic size. Meanwhile, Chicago's overlay of north/south and east/west addresses, all measured from the State and Madison interesection creates a city as easy to negotiate as a real grid with x and y coordinates. DC, as a planned city, managed to grid itself nicely, too, although the grid often gets lost in the diagonal streets with state names and all the circles. San Francisco feels more like an eastern or midwestern city than any out west due to its strongly gridded streets. So...is Chicago, in fact, the most gridded? If not, what could possible have that title of "Single Greatest Grid"? And what unique stories do other cities than the ones mentioned here bring to the subject of grid development?>