These are gross generalizations but there are basic similarities and differences between the
19th Century rowhouses you'll find in various areas of the Northeast. This is just based on my own observation and have no academic architectural backing.
Rowhouses in the NYC area tend to have a bit more dimension on the front face. Bow windows are common or various types of texture between the parlor and upper floors. They also tend to have more steps between street level and the parlor floor. Here's a pic of a typical Brooklyn brownstone...
In North Jersey you see the high parlor floor, but less variation in front face. There are occasionally arched treatments above the front door, and rarley even above windows. Most windows tend to appear entirely rectangular. Here's a pic from Hoboken...
and in Jersey City...
In Philly the rowhouses in Old City tend to be closer to the ground. They have relatively flat front facades. They are very Federal in their design. They often include window shutters or and occasionally gables.
The rowhouses pictured from Trenton seem to blend these characteristics of NYC/NNJ and Phila fairly well. The entrances are low to the ground like Philly, but their shape and ornamentation are like those seen in Jersey City. They're quite attractive, IMO.
There are of course exceptions to these rules, and 20th Century rowhouses developed with different styles entirely.