After remaining persistently high early in the summer, gasoline prices have tapered slightly in recent weeks. Drivers in some states, however, continue to feel the pinch at the pump.

National gas prices have fallen by six cents over the past month through July 16. But this lower-than-expected drop has not been enough to provide consumers with much relief, Avery Ash, Director of Federal Relations for AAA, explained. “For the last several months we’ve seen prices staying stubbornly high at a time of year when motorists are used to prices declining.”

Click here to see the states with the highest gas prices

Geographical location often impacts gas prices in a state. “Proximity to refineries can help with cutting down the distribution costs,” Ash said. Average gas prices in Texas — the state with the most refineries — are generally 14 cents lower than the national average prices. By contrast, states in the Northeast often pay higher gas prices, given their distance from oil-producing and oil-refining states. With the exception of California, all the states with the highest gas prices have fewer than 10 refineries.

When it comes to gasoline, “California is a bit of an island,” AAA’s Ash told 24/7 Wall St. State fuel regulations isolate California from neighboring states, requiring it to rely on in-state refineries. “If a California refinery goes offline, which is often the case during the spring transition periods or during the summer, it can have an effect on retail [gasoline] prices,” Ash said. State regulations make it harder to supplement in-state production with gas from other states, often creating large fluctuations in California’s gas prices.

Taxes are also an important component of the final price at the pump. States such as South Carolina, Alabama and Missouri — which have the cheapest gas prices — also have among the lowest gas taxes. Seven of the states with the highest gas prices have gas taxes above the national average of 31.2 cents per gallon. California, which has the third highest cost of fuel, levies a tax of nearly 50 cents per gallon, higher than all but one other state.

Some of the states with the highest gas prices have higher prices for consumer goods in general. However, as Ash explained, differences in regional consumer prices are likely not particularly important to gas prices. “The bulk of the difference in prices can be accounted for at state level taxes,” he added.

Based on figures from AAA’s Daily Fuel Gauge for July 16, 2014, 24/7 Wall St. identified the 10 states with the highest gas prices. Additionally, we also reviewed refinery counts from the Energy Information Administration (EIA), current as of the start of 2014. Figures on state and local gas taxes are from the American Petroleum Institute. State-level consumer price levels are for 2012 and come from the Bureau of Economic Analysis. Income figures are from the U.S. Census Bureau’s 2012 American Community Survey.

10. Vermont
>Price per gallon: $3.73
>Number of refineries: 0
>Tax per gallon: 33.0 cents (15th highest)

While gasoline prices nationwide are slightly lower than they were 12 months ago, gas prices in Vermont are slightly higher than they were this time last year. Despite Vermont’s fairly average gas taxes, gas prices in the state are roughly 13 cents higher than the per-gallon price nationwide. No oil is produced or refined within the state. Vermont also does not have any pipelines that directly deliver petroleum products to the state. Higher energy prices are unlikely to have the same adverse effects on the Vermont economy that they would elsewhere. This is because, according to the EIA, Vermont’s total energy consumption is the lowest in the nation, and it is also among the lowest per capita energy-consuming states.

9. Idaho
>Price per gallon: $3.77
>Number of refineries: 0
>Tax per gallon: 25 cents (24th lowest)

In the past month, gas prices in Idaho have risen by an average of 15 cents per gallon, or 4.1%, the largest increase in the nation. Currently, a gallon of gasoline in Idaho costs $3.77, versus an average of $3.60 nationwide. Higher gas prices may have a considerable impact on Idaho households’ budgets. The median household income in the state was $45,489 in 2012, considerably below the national median of $51,371. However, that same year, consumer prices were more than 6% lower in Idaho than they were nationwide. Although Idaho has no refineries, neighboring Oregon, Utah and Montana all supply petroleum products via pipeline or barge.

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8. Nevada
>Price per gallon: $3.86
>Number of refineries: 1 (tied, 24th highest)
>Tax per gallon: 33.2 cents (13th highest)

No state has experienced a greater increase in gas prices during the past year than Nevada. Statewide, per-gallon gas prices went up by more than 4% in the past 12 months, from $3.70 to $3.86. Taxes have likely contributed to this increase. Clark County, which includes Las Vegas and is home to a large majority of Nevada’s population, hiked its gasoline tax by 3.25 cents per gallon at the start of the year, according to the API. The county then hiked taxes by another 3.45 cents a gallon at the start of July. Yet another 3.30 cent hike is slated for next summer. Nevada’s lone operating refinery is predominantly used to produce asphalt and diesel fuel, the EIA notes.

7. New York
>Price per gallon: $3.90
>Number of refineries: 0
>Tax per gallon: 50.5 cents (the highest)

A number of factors contribute to the high gas prices in New York, including the nation’s highest state taxes on gasoline. Per gallon, New York residents pay an average of more than 50 cents in state and local taxes. Consumer prices are also typically higher in New York, at a 15% premium to national prices in 2012. This is more than any U.S. state, excluding Hawaii. While the state does not have any refineries, New York Harbor is a major hub for petroleum-based products, such as gas and heating oil, sold in the Northeast. Much of the state’s gasoline is provided by refineries located in neighboring New Jersey and Pennsylvania.

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6. Oregon
>Price per gallon: $3.96 (tied, 5th highest)
>Number of refineries: 0
>Tax per gallon: 31.1 cents (18th highest)

Gas prices in Oregon are 2.5% higher than they were a year ago, even though nationwide gas prices have fallen roughly 1% over that time. Currently, gas in Oregon costs an average of $3.96 per gallon, among the most of any state. This is despite the fact that state and local gas taxes in Oregon are roughly in-line with the nation as a whole, as were consumer prices as of 2012. While Oregon does not have any refineries, neighboring Washington is one of the largest oil refining states in the nation. Of course, the presence of refineries alone is not enough to ensure low gas prices. In fact, gasoline prices in Washington, at $3.98 per gallon, are actually slightly higher than in Oregon.

5. Connecticut
>Price per gallon: $3.96 (tied, 5th highest)
>Number of refineries: 0
>Tax per gallon: 49.3 cents (3rd highest)

Connecticut trails only two other states, New York and California, in state and local gasoline taxes, charging an average of 49.3 cents per gallon. Consumer prices were also higher in Connecticut than in all but a handful of states in 2012, which may also contribute slightly to higher gas prices. Yet, Connecticut households can also likely stand to pay more. Households in Connecticut are typically wealthier than those in most other states. The median household income in the state was more than $67,000 in 2012, or more than $15,000 above the national median.

4. Washington
>Price per gallon: $3.98
>Number of refineries: 5 (6th highest)
>Tax per gallon: 37.5 cents (9th highest)

Washington has five operating refineries, with a total capacity of 631,700 barrels per calendar day, more than all but four other states. Despite being one of the nation’s largest oil-refining states, however, gas prices in Washington are quite high. Currently, gasoline in Washington costs $3.98 per gallon, 38 cents above the national average. The state’s refining facilities have historically processed oil produced in Alaska, where production has fallen in recent years. This has led the state to pursue new imports of petroleum from Canada and the Bakken shale formation in North Dakota. Present gas prices are nine cents higher than they were at the same time last year. By contrast, nationwide prices are slightly lower than they were 12 months ago.

3. California
>Price per gallon: $4.09
>Number of refineries: 17 (3rd highest)
>Tax per gallon: 49.8 cents (2nd highest)

High levels of oil production and refining activity have not led to low gas prices in California. Last year, California was the nation’s third largest producer of oil, behind only Texas and North Dakota. The state also has the third highest refining capacity in the nation. Despite these factors, a gallon of gas in California costs $4.09, versus $3.60 per gallon nationwide. One reason for the high prices is state and local taxes, which average nearly 50 cents per gallon, or more than in any other state except New York. Additionally, California refineries operate at near-capacity due to demand and the state’s strict environmental standards, the EIA notes. These factors make gasoline prices in California especially volatile.

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2. Alaska
>Price per gallon: $4.17
>Number of refineries: 6 (4th highest)
>Tax per gallon: 12.4 cents (the lowest)

After peaking in the late 1980s at just over 2 million barrels per day, Alaska’s oil production has consistently declined to barely a quarter of that total. Yet, in 2013 the state was still one of the nation’s top oil producers, with roughly 515,000 barrels of oil per day. As a result, Alaskan oil accounts for most of the gasoline state drivers use. Additionally, state and local taxes and fees amount to just 12.4 cents per gallon, less than any other state. Yet, according to AAA’s Ash, distribution costs in Alaska tend to be higher, which can drive up the price of gasoline. Currently, a gallon of gas in Alaska costs $4.17 on average, or 57 cents above the national average of $3.60

1. Hawaii
>Price per gallon: $4.35
>Number of refineries: 2 (17th highest)
>Tax per gallon: 48.5 cents (4th highest)

No state has more expensive gasoline than Hawaii, where a gallon of gasoline costs $4.35 on average. Gas prices in Hawaii were well in excess of $4.00 per gallon during most of the past year. Hawaii’s isolated location makes it reliant on oil shipped to the state from throughout the world. In addition, the state relies on petroleum to fuel much of its electricity needs, and as a result generally has the nation’s highest household electricity rates. Gas taxes and fees also contribute to higher prices. Hawaiians pay an average of 48.5 cents per gallon in state and local taxes on gasoline, more than in all but three other states.

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