According to the most recent data from AAA, as of September 19, 2023, Delaware has the cheapest gas in the United States, with an average price of $3.434 per gallon. However, a previous report from March 2023 by GOBankingRates found that Mississippi had the cheapest gas in the country, with an average price of $2.984 per gallon. Its important to note that gas prices can vary greatly within each state and can change frequently due to a variety of factors, including state taxes, supply disruptions, and retail competition and operating costs.