something from the past that you remember:
My earliest recollections are of my mother bending over my cot.
an act of remembering something
have no recollection (of something) (=not remember)
I have no recollection of how I found my way there in the dark.
to (the best of) my recollection (=used when you are unsure if you remember correctly)
To the best of my recollection, she drives a Mercedes.
Noone, to my recollection, gave a second thought to the risks involved.