When one thinks of the richest regions of the United States, the opulence of Rodeo Drive in Beverly Hills, the high-end lifestyle of New York’s Tribeca, and the high-tech high life of the Silicon Valley may come to mind, but when ranking the wealthiest counties in the nation, the top spot went to an unassuming, small, south Texas locale.

McMullen County ranked first when Bloomberg analyzed 2015 federal income tax returns, finding Texas shale, not New York stocks, fueled the most affluent American county. Located northwest of Corpus Christi and south of San Antonio, McMullen County is home to around 1,000 people and its average adjusted gross income (AGI) reflects a staggering $303,717.

This ranching community sits on the Eagle Ford Shale formation, a natural gas and oil zone.

“I joke that oil and gas finally made ranching profitable,” Thomas Tunstall, research director for the Institute for Economic Development at the University of Texas at San Antonio, told Bloomberg. “A lot of old Texas families live on large ranches in McMullen County, and the older generation went through tough times prior to five years ago.”

Teton County, Wyoming, home to Jackson Hole, placed second with an average AGI of $248,949. New York County, better known as Manhattan, took third with an average AGI of $210,233.

Glasscock County, also in Texas, came in fourth with an average AGI of $181,375. Located outside of Midland, it sits on the recently discovered Wolfcamp shale in the Midland Basin portion of the Texas Permian Basin. Last year, Breitbart Texas reported the U.S Geological Survey named Wolfcamp the largest source of shale oil they ever assessed. It could yield up to 20 billion barrels of oil, 16 trillion cubic feet of natural gas, and 1.6 billion barrels of natural gas liquids.

Marin County, recognized for George Lucas’ Skywalker Ranch, the northern California wine country, and the tallest trees on earth, ranked fifth with an average $158,753 AGI. Fairfield County, Connecticut, with a healthy $158,253 average AGI placed sixth; McKenzie County, North Dakota, saw seventh because of a $154,013 average AGI; the Silicon Valley’s San Mateo County placed eighth sporting a $152,911 average AGI; and Pitkin County, home to Aspen, Colorado, filled the ninth spot with the average $147,271 AGI.

Another oil and gas producing south Texas county, LaSalle, rounded out the top 1o with an average AGI of $146,991. It also sits on Eagle Ford shale. In 1982, more than 90 percent of LaSalle County was devoted to ranching and farming, according to the Texas State Historical Association before shifting to a more energy-driven economy.

Money Magazine footnoted that, in 2005, no Texas county ranked among the nation’s top 30 most wealthy. However, based on 2015 data, the oil and gas producing Lone Star State counties of Karnes, Irion, Midland, Kendall, and DeWitt landed in the top 30.

Three years ago, a glut of cheap Saudi oil flooded the market leading to a major slowdown in Texas oil and natural gas production plus steep job cuts, as reported by Breitbart Texas. The U.S. energy sector rebounded in 2017 and, even though the Texas economy diversified so it no longer depends solely on oil and gas, the industry still creates lots of wealth. It also infuses millions of dollars each year into the Texas Permanent School Fund, which, in 2014, topped $37.7 billion, becoming the largest public education endowment in the nation.

The data Bloomberg compiled came from the Transactional Records Access Clearinghouse (TRAC), a research center at Syracuse University which uses the Freedom of Information Act (FOIA) to obtain statistics from various federal agencies and makes it available to the public. They sourced Internal Revenue Service County income data from the IRS’s Individual Master File of 1040, 1040A, and 1040EZ individual income tax returns filed by citizens and resident aliens.

Follow Merrill Hope, a member of the original Breitbart Texas team, on Twitter.