For your convenience, a quick run done on the various notable places to be found.
NEST: North-Eastern Seaboard Transfiguration
The NEST project was conceived as an answer to urban blight, traffic congestion, energy waste, environmental degradation, and many of the other problems presented by 20th century cities. It is a series of ten mega-structure arcologies running from Main to Pennsylvania - each providing entertainment, employment, and housing for up to half a million citizens apiece. Although some of the buildings have been completely overrun, others initiated quarantine procedures and continue as high rise islands of survivors in a sea of reanimates.
There are clay tablets from Babylon that lament the wickedness of the age and how a lack of faith is tearing apart society, and these sentiments have been present in every nation since then. New Birmingham, in the South Eastern section of the former USA is run by a theocracy who felt that the arrival of aliens and the rise of reanimates was a divine punishment a long time coming.It has the most suburban and normal seeming society of the city states, but also includes moral enforcers, an expansionist mind set, and a small army of controlled reanimate shock troopers.
Not everyone wants to see the USA restored to as it was before 2050. Some feel monitored nano-tech, drone armies, and planned cities were only the tip of a totalitarian iceberg. The ridge is a mostly agrarian society that attempts to
Free City of Tesla
Although its more of an underground complex than a city - the free part is certainly true. Comprised of trans-humanists and anarchists they are using the current lack of oversight to experiment with computer assisted cybernetic hive-minds, genetic manipulation, alternate social moores, and rumors of even more.
Wide open terrain, combined with the range advantage of Rail-guns over Lasers means that the desert was the site of significant victories for the army over the invading planetary citizens. However, now the remains of multiple battalions, bits of the US government, and the civilian population are all isolated in the middle of nowhere with limited supplies and even more limited contact with the rest of the country.
An incomplete arcology complex, and eventual nuclear power industry site, currently the main draw of this Texan town is the relative safety of its structures, and its proximity to the LOST-SEC Gulf naval facility, with its attendant nuclear powered cruisers. Furthermore, Lone Star may be the headway to the path around the Citizen forces that have mostly cut the Western seaboard off from the rest of the country.
Kola Command Authority
For all intensive purposes, the Russian North Fleet, in conjunction with elements of other Baltic powers, has "gone Viking". Cruise missile submarines track the few remaining cargo vessels while hovercraft make inland forays for supplies. The long-term plans of these raiders is still unknown, but their control of several dozen nuclear tipped ICBMs and torpedoes means they'll eventually become a major power-block when rebuilding is finished.
Not so much an area as a border marking, some of the aliens have begun settling areas of the Earth. Their towns are small, and mostly comprised of homes looking like clusters of soap-bubbles made from clay - though some also include airstrips to receive shuttles and fighter craft. Most humans never get that far, however, instead meeting the multi-story tall phased array energy projectors and their attendand surface-to air missile launchers.