The first federal gasoline tax in the United States was created on June 6, 1932 with the enactment of the Revenue Act of 1932 with a tax of 1¢/gal. Since 1993, the U.S. federal gasoline tax has been 18.4¢/gal. Unlike most other goods in the US, the price displayed includes all taxes, as opposed to inclusion at the point of purchase.

About 60% of federal gas taxes are used for highway and bridge construction. The remaining 40% goes to earmarked programs. However, revenues from other taxes are also used in federal transportation programs.

Don't understand why the tax is included in the price at the pump. I guess it's the government's way to try to keep you from knowing how much they're sticking it to us.

Below is a link to an interactive map of the US showing each states gas taxes. At least Tennessee's gas tax isn't as high as some others.