Ward 4 is on the East side of Manchester, between Union Street on the West and I-93 exits 6 and 8 on the East.  The best way to determine your voting ward is to use this map from Manchester's City Government site (we're the lighter pink region): 

I've also outlined a quick map over some Google data:

Or, if you prefer a cleaner picture, with the Google map removed:

I live on the eastern side of the ward, so my wife and I get to enjoy ice-skating on Stevens Pond in the winter and walking to Manchester's best and possibly, only, Nepali restaurant.  I look forward to getting to know the rest of the ward through this campaign!