When you pull into the gas station to fill up your car, do think about how that gasoline got there? We tracked down it's path and found that where South Dakota's gas comes from affects how much you pay at the pump.

The gasoline that goes into your vehicle's tank arrives in South Dakota from one of three pipelines. The Magellan Pipeline comes into the state in Sioux Falls and Watertown. You'll find terminals located in both of those cities. Most of the product that's carried through these lines is being produced in the Twin Cities area of Minnesota.

The NuStar Pipeline is the biggest in South Dakota. Gas in this line first arrives in Yankton, then it heads to Mitchell where there's another terminal. It continues north to the small town of Wolsey, South Dakota and then moves on to another terminal in Aberdeen. NuStar also has an extension of its pipeline that serves a terminal in Sioux Falls. Most of the gas in this pipeline comes from the southern United States.

The Plains Rocky Mountain Pipeline enters the state in Rapid City. It's a smaller pipeline but it's first priority is supplying Ellsworth Air Force Base. In fact about three times a year, the pipeline only carries jet fuel, and not gasoline, to supply the aircraft at the base.

Once the gas is delivered to terminals, trucks carry it to gas stations all around the state. But when supplies get low, truckers sometimes have to go outside of the state to get their supplies.  That means you'll pay more at the pump because of transportation costs.

Dawna Leitzke, the Executive Director of the S outh Dakota Petroleum and Propane Marketers Association tells KSFY that South Dakota is unique in that some of it's cities, like Rapid City and Aberdeen, are at the end of the pipeline.  That means larger cities like Chicago and Kansas City, that are farther up on the pipeline, might get the gasoline, instead of those at the end of the South Dakota towns at the end of the line.  She says they try to use gasoline from inside South Dakota as often as possible.  But when supplies are scarce, truckers have no choice but to get it from other states, such as Nebraska, Iowa and Kansas.