I'm wondering how I can get a list of all the trips I've made to the US over the last 4 years. When calculating the time I've been in Canada, it asks me to list them to see if I've been here enough days yet. I live right by the border so I go over there a couple of times a month for dinner or groceries or camping but I never realised I should've kept track of the dates.

I'm thinking that if I only left for a few hours hours then I won't need to list those trips, just anything where I stayed overnight. Thoughts?

If you leave Canada and come back the same day, you do not have to declare an absence.
https://eservices.cic.gc.ca/rescalc/...A?redir=faq#Q3

I suppose you could do an Access to Information request for your entry record from PAXIS if you really want to, which raises the question why CIC don't just do that rather than making you list it all on the application. I heard they were going to.

You can also do a Privacy Act request to CBP on Form G-639 for the same information from the US side.