Most oil and gas dependent counties in the US are…

Pressured by a glut in supply, oil prices have cratered in recent months and hit their lowest level in nearly six years this week.

While many gas guzzlers are benefiting from the drop in prices, numerous oil-rich clusters around the U.S. will see an impact from by the commodity's decline.

So where are the most oil-dependent spots in the U.S.?

Washington County, Oklahoma, topped with the list, according to data from the Bureau of Labor Statistics.

Read MoreEnergy MLPs in the red: Investors running scared

The BLS measures relatively concentration through determining a "location quotient" in each county. Any number great than 1 means a county's oil and gas extraction concentration is greater than the broader U.S. Washington County has a location quotient of nearly 140.

Upton County, Texas and Woods County, Oklahoma, came in second and third respectively.

Texas accounted for half of the top 10 counties while Oklahoma contributed two. Counties in Utah, Kansas and West Virginia rounded out the list.

Read MoreOil: Why nobody knows how low it will go