America's leading producer of construction essentials such as crushed stone, gravel, and sand, Vulcan Materials is based in Birmingham, Alabama but boasts facilities in 20 states and DC. Dating back to 1909, the firm weathered the Great Depression and prospered during World War II, when it played an important role in the war effort supplying aggregates and concrete for the Manhattan Project. The company went public in 1957 and has since gone from strength to strength.

Super-valuable businesses are thin on the ground in the Last Frontier given its geographical isolation from the Lower 48. In fact, the most valuable public company in the state, First National Bank Alaska, is worth a relatively paltry $597.2 million (£456.6m). Founded in 1922, the Anchorage-based bank has 31 locations across the state.

Arkansas is home to retail behemoth Walmart, which is the world's largest company by revenue with an annual turnover reaching nearly $524 billion (£415bn) in the 2020 financial year. The firm's late founder Sam Walton opened the first store in the city of Rogers on 2 July 1962 and the rest is history. These days the company, which is based in Bentonville, has over 11,300 locations in 27 countries and serves more than 270 million customers per week.

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California is awash with exceedingly valuable businesses, from Alphabet and Facebook to Disney and Tesla, but the most valuable of them all is Apple. In August 2018 the Cupertino-based tech giant, which was founded by Steve Jobs, Steve Wozniak and Ronald Wayne in Jobs' childhood home back in 1976, became the first public firm on the planet to hit a trillion-dollar valuation, and it remains the most valuable public company globally.

Health insurance titan Cigna is Connecticut's most valuable firm. Its origins date way back to 1792 but the company as we know it today was formed in 1982 as a result of the merger between Connecticut General Life Insurance Company (CG) and INA Corporation. At the current time the corporation, which counts more than 70,000 employees, has more than 180 million customer and patient relationships in over 30 countries and jurisdictions.

The COVID-19 pandemic has knocked Boeing off the top spot in Illinois. Unsurprisingly, the ailing aerospace company has been eclipsed by a biopharmaceutical firm, AbbVie, which has seen its stock market value surge during the crisis for obvious reasons. Founded in 2013 as a spin-off of Abbott Laboratories, the Chicago-based company is working to develop an antibody treatment for the virus.

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Along with several other states in our round-up, Minnesota's most valuable company specializes in healthcare and medical insurance. Based in Minnetonka, UnitedHealth Group was created in 1977, went public in 1984, and now boasts 325,000 employees serving millions of people worldwide.

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Given farming is the leading industry in the Magnolia State, it stands to reason the most valuable Mississippi-based firm is an agricultural company. From its humble beginnings in 1947 as a small-scale feed and seed business, Sanderson Farms, which operates out of the city of Laurel, has expanded to become the nation's third biggest poultry producer, processing 13.6 million chickens per week.

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A litany of high-value firms are headquartered in Ohio including retailers Macy's and Kroger and tire giant Goodyear, though these companies are worth considerably less than the state's number one Procter & Gamble. Founded in 1837 by English chandler William Procter and Irish soap maker James Gamble, the Cincinnati-based consumer goods corporation owns iconic brands that are famous the world over including Ariel, Gillette, Pampers, and Tampax.

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Washington is home to not just one but two companies valued in excess of a trillion dollars: Amazon, which is worth $1.59 trillion (£1.22tn), and tech giant Microsoft, which pips it to the post. Founded in 1975 by Bill Gates and Paul Allen in an Albuquerque garage, the tech giant has brought the world everything from the Windows operating system to Office, Xbox, and Azure cloud services.

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Financial technology company Fiserv is America's largest independent processor of checks and one of the nation's three leading data processing companies. Founded in 1984, the Brookfield-headquartered business now supplies software solutions to thousands of financial institutions and millions of businesses around the world.

America's least populous state has a dearth of public companies. The former most valuable firm, Cloud Peak Energy, recently emerged from bankruptcy and is now worth a pittance. The only other publicly-listed Wyoming-based company we have identified is the colorfully-named Crazy Woman Creek Bancorp, the parent of the Buffalo Federal Savings Bank. But it is worth 150,000 times less than Apple, the most valuable business in our round-up.

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