There are special (usually positive) issues for Canadians as related to being in the US, even if they “overstay.” The reason is that the US government is not clear about whether Canadians who entered without a visa and who stay longer than 6 months actually have “overstayed.” If you are Canadian, the best course of action is to not stay longer in the US if you entered without a visa. If you did stay in the US more than 6 months (on this entry or prior entries), you need to speak with an experienced immigration attorney to determine if and how this will affect your eligibility for a green card.
If you need to talk to an experienced immigration attorney. We’ve helped hundreds of people traverse the complicated immigration and citizenship process. We would love to help you as well. Call (617-766-0214) or email firstname.lastname@example.org to get in touch.