Alaska has the lowest combined state and federal tax/gallon, 26.4 cents, but some of the highest transportation costs, hence gasoline is expensive.
California has high combined state and federal tax/gallon, 50.4 cents, but transportation is relatively low.
Some cities have a separate tax which is added.
Add sales taxes.

Most of the swings in price are the result of the price per unit in commodities trading on the NYMEX exchange in the U. S. The price depends on world supply and demand.

In Canada, taxes are about 1/3 of the cost/gallon. An interesting chart or two are found here: Oil and Gas Prices

One might conclude from these that Canadians pay more for the privilege of buying gasoline, despite the fact that Canada produces most of the gasoline it uses.

From another thread, updating a figure by ALCAN1:
Canada exports 1.77 million bpd, but imports 850000 bpd (to supply some East coast areas). 2006 figures from Canadian Assn. Petroleum Producers.