It's a difficult thing to figure out in some ways. Your local telephone book describes the bounds of local calling for landlines, but they often don't match the local calling area for cellphones, or at least in my area they don't match. Traditionally, if you make a call on your cellphone without the 1- you get a warning if the call is long distance, before the call is completed. As you move geographically, the town you are in becomes a local call.
Ultimately, the only way to determine this is by trial and error.
Outgoing calls would usually be considered local though you'd want to double check your plan as some more basic ones might consider it roaming. Anyone who calls you when you're away would be calling long distance if you're away from your home calling area. Many cell plans have nationwide minutes these days so long distance doesn't really exist for those plans in a way anymore.
This is how I understand it to work:
Inbound calls: People pay long distance if applicable to reach you based upon where your number is based. For example, if your number is based in Toronto and someone calls you from Ottawa, then they pay long distance to Toronto. If you are not in Toronto, then they pay long distance to Toronto and you pay long distance from Toronto to wherever you are.
Outgoing calls: When you are home, then you can call anywhere in your local calling area. However, when you are away from home, then places local to the tower where you are connecting are local calls and calls away from that area you're in (including to your home area) are long distance.
There are defined "rate centers" but sometimes the mobile companies have different setups than the land line ones. Note that I am giving you what is my understanding only and any questions regarding rates to other numbers should be made to your carrier. However, if you want to putter around and see how it works, then there are websites that assist. If long distance is a concern to you my advice is to get a plan which includes it. That's what I have and so I don't have to spend any effort at all wondering if something is "long distance" or not...