National gas price information is available through the U.S. Energy Information Administration, or EIA, and a privately owned website, GasBuddy.com. While the government owned website, EIA.gov, provides weekly gas price updates, the information on GasBuddy.com is updated within 24 to 36 hours.
Information on the EIA site is updated every Monday and groups the statistics according to geographical area. An overall average is also given for the entire nation. The weekly information is compared to the prior two weeks, as well as with the same week during the prior year. Gasoline and diesel are listed separately.
GasBuddy.com is an interactive gas price searching website that also features a USA National Gas Price Heat Map that shows nationwide price comparisons at a glance. The color coded map has a bar graph that notes the average price for a specific area. California and a small part of Nevada are in the deepest red, showing they have the most expensive gas in the nation, as of March 2015. A link leads to a similar map for Canada.
State and individual gas price averages are also available on GasBuddy.com. The main page lists the average prices, low to high. Click on a state, and a search field comes up to find gas prices in a particular city. Canadian gas price information is also available for comparison, either by province or city.