These are calls made within your own state. These calls are subject to an entirely different set of tariffs independently set by each state. If you make more Intrastate calls than Interstate calls, make certain the plan you choose gives you the best possible rate. Too many consumers are lured by low-ball State - to-State rates only to get gouged on their in-state calls.
With respect to natural gas companies, the transporting and sale of gas for resale within the boundaries of a state.
A shipment originating and terminating within one state's boundaries.