Can a permanent resident of the United States travel to Canada without a visa?

I'm a permanent resident with a Dominican Republic passport. Do I need a visa to travel to Canada?

I think now a days you need a passport to travel just about EVERYWHERE. you use to not need a passport to go on a cruise, now you do, so now I gotta get me a passport so I can go on a cruise

No, you do not need a visa. You can use the site below to verify this. just enter your nationality, enter that you are a permanent resident of the U.S.A., enter your destination, and click for the info. You will see that you do not need a visa for Canada.

you do not need a visa if you hold a US green card

Charlie is correct, although you will need a passport to return to the US by air.