Place ham in a large 6-8 quart slow cooker, cut side down. (Remove a few slices from the cut end of the ham if necessary to fit.) Transfer as much liquid from the ham packaging to the slow cooker as possible.
In a small bowl, combine the brown sugar and cinnamon.
Pour the brown sugar mixture over the ham, packing it down to form a crust on the top of the ham.
Drizzle the honey over the top of the ham.
Cover and cook on low for 4-6 hours, until the ham reaches 140 degrees in the center. (Measure temperature during cooking with a probe-style meat thermometer.)
Remove from slow cooker and let rest for 5 minutes before carving.