In the United States, the term interstate pipeline company refers to a gas pipeline that crosses state lines. Pipelines that stay within the boundaries of a state are called intrastate pipelines. The distinction is important because interstate pipelines are regulated by the Federal Energy Regulation Commission (FERC), whereas intrastate pipelines are regulated by the state in which they are located.
The U.S. has a large network of interstate pipelines that move gas from supply basins to markets.
Map of interstate and intrastate pipelines in the U.S.
Source: U.S. Energy Information Administration