Where can I find photocopying poster-sized paper (poster quality)

Check Uprinting. You can beat prices if printing large numbers of posters, but they are worth looking at for a 1-of or just a few copies.

Edit by me. I answered on the wrong question again.

Kinko’s can do very large sizes. I once had something printed that was about 4 feet by 6 feet, from a soft-copy original. It came out just fine.

Oh—you’re asking where to buy the paper? Sheets or rolls of heavy stock, poster-weight? I thought you were asking where you could get the photocopying done.

I’d search on art supplies, printing supplies, and photocopying supplies for starters. Or visit a store such as Staples that sells poster board and see what they can special-order.

Oh, oh, oh… You did say where to get poster paper. I was in an AC More Art & Craft Store yesterday. They had it, as well as project board to mount it.

Art stores like Aaron Bros., Michaels, Hobby Lobby, Pearl, that kind of place if you don’t want to pay markup and go to a Kinko’s or commercial copy service place.