First all, I made no distinction between my son or daughter.
I was always a bit nervous but I did allow them some freedom at 11ish. Basically, they couldn't leave the block without asking and couldn't leave alone. There were a ton of kids where we lived. We generally knew all the parents phone numbers as well. Sometimes we'd get call verifying our neighbors' kids whereabouts/ sometimes we'd call. Having that system was very helpful.
I won't say I was never nervous but I think having some freedom helped both us and our kids.
Once in 6th grade we got them cell phones. And yes we did track them (only when we didn't know where they were). We let them know the deal and stopped when they were seniors in HS.