Maryland

The dog must be on a leash for tracking. No special examination or licensing is required. You must notify the conservation ranger before beginning tracking. You are not allowed to dispatch a deer at night.

State Regulations: http://www.dnr.state.md.us/sw_index_flash.asp

United States:
Canada:

Green — Tracking allowed
Red — No Tracking allowed
Gray — Tracking allowed under certain circumstances or in certain areas of the state/province, but not all