I am fasinated with shooting replica Sharps & rolling block rifles both standard and odd calibres from the American West

Despite web searches, I can't find a lot about buffalo herds today; management , locations, current numbers etc., in areas other than Texas (they have an excellent site -http://www.texasbison.org/bisonstory.html)

Are they kept mostly in National Parks and are there any herds further north say in Canada?

I think there are private herds located all over the US, as well as herds found in parks and on public land. Several posters report on cull hunts as well as trophy hunts during the year. Seems like you can collect a ton of steaks for a fair price. Logisitics is the only thing keeping me out of that gamne.
I think Ray Atkinson advertises a hunt for free roaming buff in Utah if memory serves. He says it is one of the hardest hunts going, so its probably a real ball breaker.
John the Greek also posts about his buff hunts from time to time. You might try contacting him also.

Sir: If you pm a mail address to me I'll send you a copy of our black powder cartridge magazine from a few months back that had a very good article on fair chase buffalo hunting/sharps rifles/killing effect of cartridges and bullets. please send me an Australian equivalent magazine on hunting, or at least one with great pictures. ned, plunking around with the "big fifty"

You have PM and I would be glad to do likewise.