I just made a set of maps as part of my thesis project for @dillonm and @AMReese07. These are activity density (jobs plus residents) by quarter-mile radius hexagons, and all are at the same scale.

Darkest blue: > 20k / sq mi
Middle: 10k - 20k / sq mi
Lightest: 5k - 10k / sq mi

Baltimore and Washington, with Frederick and Hagerstown to the northwest and Annapolis forming a right angle with Baltimore and Washington.

Note just how patchy and spread out the development in Northern Virginia is.

Philadelphia, with Wilmington to the southwest and Trenton and the New York suburbs to the northeast. The parallel line of cities in the Great Valley of the Appalachians are, west-to-east, Lancaster, Reading, and Allentown-Bethlehem

New York City. Trenton is just at the lower-left, Newburgh at the upper center, and New Haven at the upper left.

The closest thing the Northeast Corridor has to an empty zone: Connecticut, Rhode Island, and Western Mass. The line of cities in the center-left are, north to south, Springfield, Hartford, and New Haven. Worcester is in the upper-right and Providence is in the center-right.

Finally, Boston and its surrounding ring of old mill towns and smaller cities: The ring of cities, going counter-clockwise from the northeast, are Haverhill, Lawrence, & Lowell on the Merrimack (Nashua just NW of Lowell), Worcester, Providence, Fall River, and New Bedford.

For a view further north, the Merrimack mill towns are now at the bottom of the frame, Portland is in the far upper-right, and Manchester is north of Nashua. Concord is a little beyond that.

A good deal south of Washington, along the James River, we have Richmond (right) and the sprawling and seemingly-centerless Seven Cities of Hampton Roads. (cc @lessequalmore)

Continuing the leaps south, we have the Piedmont Triad (Winston-Salem, High Point, and Greensboro) and the Research Triangle (Chapel Hill, Durham, and Raleigh). All much smaller and more spread out than what we saw further north. (cc @blackurbanist and @misplaced_mic)

I was a bit surprised by how small and far from things Charlotte was:

Atlanta has long tendrils along freeways. (cc @dillonm and @ColinVParker)

This view of Cleveland (with Akron and Canton to its south) and Pittsburgh supports my impression that Pittsburgh has more of an actual dense core left. (cc @alexbaca, @shadow, @GracieOfKalmont, and @riversidewings)

Finally, Columbus (upper-right), Dayton (center), and Cincinnati (lower-left).

I hope you've all enjoyed this tour!