Canadian citizens have long enjoyed special rules for entering the United States on various types of visas. Most notably, the majority of Canadian citizens do not need to visit a U.S. consulate in advance of their travel in order to obtain a visa to enter the United States for a temporary stay. Canadians also enjoy access to preflight inspection procedures, in which they clear U.S. immigration and customs before boarding the plane. This both saves time and hassle if they are ultimately denied entry into the United States.
When it comes to green cards, however, Canadians are in most respects treated the same as any other immigrants to the United States. But their access to certain special types of temporary visas, such as the TN, may help them establish a relationship with a U.S. employer willing to sponsor them for a green card.
The exception is American Indians born in Canada, who are considered to have a right to enter the United States, and can apply for a green card after proving their lineage. This includes all Canadian-born persons with 50% or more American Indian blood.
Under the NAFTA treaty, Canadians (as well as Mexicans) who practice certain professional occupations and who have a job offer from a U.S. employer may apply for TN status. It lasts for one year, and can be renewed in one-year increments, with no limit on renewals. For a list of the qualifying occupations, see the NAFTA Web page.
While in the United States on a TN visa, it is NOT acceptable to apply for a green card. Some visas, such as the H-1B allow "dual intent" -- that is, simultaneously assuring the immigration authorities that you are planning a temporary while also pursuing the possibilty of a green card -- but the TN is not one of them. Your best bet is most likely asking the employer for whom you are already working to petition for you to receive an H-1B visa, and then to seek permanent residence.
If you are eligible for a green card due to your American Indian blood and birth in Canada, you must make an INFOPASS appointment with a U.S. Citizenship and Immigration Services (USCIS) office within the United States. At that appointment, you will request that a record of admission for permanent residence be created for you. There is no particular application or form that you need in order to apply for a record of admission for permanent residence in these circumstances. You also must submit the following items to USCIS:
Other non-Indian Canadians must apply for permanent residence in the United States much in the same manner as citizens of other foreign countries. Commonly used eligibility categories include through a job offer in the U.S. or a close family tie to a U.S. citizen or permanent resident.
One advantage that Canadian citizens do have, however, is that it is very easy for them to enter the United States legally. With a legal entry, it becomes much simpler for those who become eligible for a green card – for example through marriage to a U.S. citizen – to get through the various procedural hoops and apply for the green card without having to leave the United States.
If you are a Canadian citizen and you wish to seek permanent residence in the United States, you may wish to seek counsel from an experienced U.S. immigration lawyer. An immigration attorney can advise you as to the easiest and most efficient path to U.S. permanent residence.