VGFacts

So basically nobody knows the official USA release date of Super Mario Bros. for the NES. Wikipedia says it was released in the year 1985, the same year it was released for the Famicom. But it doesn't give us the exact day and month it was released on.

http://en.m.wikipedia.org/wiki/Super_Mario_Bros.

However, the Mario Wiki states that it released October 18th, 1985.

http://www.mariowiki.com/Super_Mario_Bros.

Could this be the actual release date? I'm not sure if it is.

Wikis are edited by people, not officials. We have no way of knowing. It's believed it was released over several different days and so there is no confirmed time - you have to realize that the business was far different in those days. Restrictions on releases were far more loose.

At the least it should have been within the same month.