Upon returning to Canada

It's been 1 month to the day that I returned to Canada after spending almost a year in California on a TN-1. It just recently came to my attention though, that perhaps I should be telling someone from US C&BP that I've left their country, so that they don't think I've overstayed my welcome and prevent me from coming back even on a short visit. I've searched many websites and tried every combination of keywords I could think of to search this site, but I haven't seen any information. Is there anything I should be doing?

If you still have your I-94 you need to return it to the service centre in Kentucky with a letter of explanation, i.e. it's multiple entry so you kept it but you're not going back so you're now returning it.

ACS - CBP SBU
1084 South Laurel Rd
London
KY 40744

Don't have it: The Customs official asked if I'd need it again as I entered Canada through Sarnia. I didn't, so he took it. All set then?

Thanks muchly, it's a relief.

If you surrendered it to CBSA when you left, that's the end of it.