There are several reasons why gas prices differ across USA. These include:

1. Crude Oil Prices: The price of crude oil, the main raw material used to produce gasoline, is a major factor in determining gasoline prices. Crude oil prices can vary based on global supply and demand, geopolitical events, and other things that affect the cost of production and transportation of oil and gasoline.
2. Regional Demand: Gasoline demand can vary widely across different regions of the United States, depending on factors such as population density, demographics, and economic activity. Areas with higher demand for gasoline typically have higher prices due to increased competition for limited supplies.
3. Refinery Capacity and Location: The location and capacity of refineries can affect gasoline prices. Areas with a high concentration of refineries, such as the Gulf Coast, may have lower prices due to increased competition and lower transportation costs. Conversely, regions that are further away from refineries or have lower refinery capacity may have higher prices due to increased transportation costs and lower supply.
4. Taxes: State and federal taxes can also affect the price of gasoline. Taxes can vary widely across states and countries and can account for a significant portion of the retail price of gasoline.
5. Market Competition: Market competition between gas stations and retailers can also affect gasoline prices. In areas where there is more competition, prices may be lower due to retailers competing for customers. Conversely, areas with less competition may have higher prices due to limited choices for consumers.