It depends what you want to listen to.
Niagara Regional Police, who do all the cities and the regional highways are 100% digital and encrypted, so that's out. The Niagara Parks Police who do the Niagara River Parkway are Digital, but I'm not sure if it's encrypted - They are on 142.8600.
There's the Ontario Provincial Police (OPP). They are on a VHF SmartZone system and are digital but in the clear. You can grab the system info from here:
http://www.radioreference.com/modules.p ... sysid=782d
You are going to want to program in Site #13 (Niagara Falls). The OPP in Niagara are on Talkgroup 1OPS43 (8736 decimal, 222 hex), and is almost always patched with 1OPS39, so depending on your scanner, you might need to scan both of them.
Ambulance are on the same system as the OPP, except they are analog. You can find Niagara Ambulances on 2 talkgroups, NIA North and NIA South, again listed at the above link.
Fire Departments are (for the most part) VHF analog conventional. You are going to want the following:
Fort Erie: 148.5400
Grimsby/Lincoln: 155.9100
Niagara On The Lake: 153.7700 and 150.7550
St. Catharies: 155.4450
Welland/Port Colborne/Wainfleet: 153.8000
Niagara Falls Fire however is a different beast. They are on a UHF MPT1327 trunking system. They dispatch on 150.5450 and sometimes use 153.8000. Their operations can be found here:
http://www.radioreference.com/modules.p ... R&sid=3341 It's not that busy of a system, so chances are if you scan them conventionally, you'll be alright.
Some others you might want to throw in there. All ambulances in Ontario carry voice pagers which are used to tone out the ambulances, much like a volunteer fire department. They are on 149.4400. The Police have a provincial common of 142.7700 as do Ambulance (150.1000) and Fire (154.0700).
If you listen to all of those, you probably won't miss anything going on in the area.
Have fun!
