ALL PHOTOS ARE MY OWN, AND HAVE BEEN LICENSED UNDER CREATIVE COMMONS
I don't have photos up, but Caraleigh in Raleigh and Royall Mill Village in Wake Forest are two rare examples in Wake County, NC (population 1.15M).
Some mill villages which have much denser housing than their mostly-detached metropolitan surroundings:
Manayunk, Philadelphia, PA
Manayunk by
Payton Chung, on Flickr
Also interesting because of the very steep topography surrounding it, which is quite a contrast from central Philadelphia's flatness.
Pullman, Chicago, IL
Pullman rowhouses by
Payton Chung, on Flickr
Pullman was a company town built around George Pullman's railcar factory. Its rowhouses are unusual for Chicago, where fire codes generally required separating buildings.
Hampden, Baltimore, MD
A ride on MTA Baltimore light rail by
Payton Chung, on Flickr
Meadow Mill is right behind a light rail station that's built on what was an industrial railroad that snaked along the Jones Falls River, which powered a series of mills which largely made sailcloth.
Some mill towns that were incorporated into large metros' suburbs:
Marktown, East Chicago, IN
Across the park by
Payton Chung, on Flickr
This 1917 town was only ever 1/4-built and is surrounded by steel mills and oil refineries southeast of Chicago. Howard van Doren Shaw, better known for palatial suburban estates, designed a series of picturesque Cotswold-ish one- and two-family cottages on tiny plots arrayed on a tight grid of intimate streets.
Savage, Howard County, MD
Savage Mill, view from tower by
Payton Chung, on Flickr
The former textile mill, which briefly was converted into a factory for Christmas ornaments, is now an antique mall. Duplex houses from the mill days (unusually dense for a county where 78% of houses are single-family) are visible just beyond.
Ellicott City, Howard County, MD
(Howard County is a suburban county of Baltimore with 330,000 residents but no incorporated towns or cities.)
Ellicott City, Maryland by
Payton Chung, on Flickr
The city's dramatic topography made it a terrific location for grain mills, and its early status as an industrial center means it was the terminus for America's first railroad line (the B&O, from Baltimore) and the county seat. The topography has also contributed to several devastating floods in recent years.