I am the person who originally posted this query in 2012. I still watch the series. The ninth season just finished its run in the United States, when Amy and Ty FINALLY got married. The only location Heartland has aired in the US since the first two seasons had been syndicated is the Up channel, which used to be GMC. Heartland aired at 9 p.m. eastern time on Wednesdays in the US.
Up has periodically shown weekday reruns as well, but the channel is not doing that at the moment.
I've always considered Heartland to be very uncool, which is why I like it. It's reminiscent of Bonanza/Big Valley/Waltons/Little House/Dr. Quinn, although it is contemporary. The CBC shows the series on Sunday nights.
I don't know why the syndication packages ended around the US. The only difference I've noticed between the syndicated version and what airs on Up is that the few occasional curse words (there aren't that many, and they're mild!) get edited out on Up! I've also learned a lot about western Canada geography by watching this.
P.S. Up currently has a new drama called Ties that Bind airing at 9 p.m. eastern time on Wednesdays. It's about a female police officer, her husband and children. They've taken in her brother's children because she arrested her brother for selling drugs and he is now in prison.
= new reply since forum marked as read