Retailer REI, which is based in Washington state and has 12,000 employees, scooped the accolade for its 20th consecutive year.
The 6million-member co-op is placed 28 in the ranking and is one of just 12 companies to be included since the annual list began in 1998.
“This is an amazing honour and we are all very proud to be recognised for 20 straight years,” said chief executive and president Jerry Stritzke.
“Our placement on this list for the past two decades is a reflection of our employees throughout the country, so I want to thank all of them for making REI a great place to work.”
He added: “We put our purpose above profits and I think that’s a huge reason why people love working here, stay here for a long time and do such great, impactful work.
“Our employees have had a passion for the outdoors since our founding in 1938, and that passion continues to unite and inspire us, giving each of us a strong sense of what matters most, no matter where we live or work.”
Fortune compiles its list through an extensive survey of more than 276,000 employees at companies with more than 1,000 employees. The assessment includes the honesty and quality of communication by managers, support for employees’ personal and professional lives and the authenticity of relationships with colleagues.
Surveys at REI – which sells sporting, outdoor and camping gear and offers outdoor holidays and courses – found engagement levels routinely exceed 85%, while 93% of co-op employees believe in the co-op’s vision.
Its combined pay and benefits lead the industry, retail turnover is almost half the industry standard and retention of full-time employees is 90%. There are also product discounts and an insurance and medical plan.
Employees get two paid “Yay Days” off to take part in a favourite activity, learn something new or work on an outdoor stewardship project. Another paid day off comes on Black Friday, when the co-op turns its back on a day of frenzied retail activity, closing its 147 stores so workers can spend time outdoors with family and friends.
REI also provides workers with showers, towels, lockers and bicycle storage at most of its sites, and offers a 50% pre-tax subsidy on public transit expenses, parking subsidy, and subsidy for vehicle pooling and ride sharing.
Mr Strizke recently spoke out against moves by president Donald Trump to place travel restrictions on seven majority- Muslim countries and has personally offered assistance to employees who have been affected.
Navy Federal Credit Union also made the rankings, at number 47 – its seventh year on the list.
Founded in 1933 to serve members of the armed forces, it is the world’s largest credit union, employing 14,153 people across 273 sites, with revenues of $4,720.4m.
“Navy Federal is an outstanding place for a career,” said president and chief executive Cutler Dawson. “We believe that employees should come first in any organization. Creating a work environment where people can learn, prosper and grow while being part of a team they believe in is what a great place to work is all about.”
Fortune cited Navy Federal’s employee retirement programmes, performance pay incentives and loan discounts. Workers can also receive tuition reimbursement for undergraduate and graduate educational courses and textbooks, and the company runs three scholarship programmes.
Its “Dollars for Doers” scheme encourages volunteering, awarding non-profit organisation grants of $1,000 on behalf of colleagues who volunteer.
Fortune also commented on the credit union’s “innovative” workplaces, which include convenience stores, state-of-the art fitness centres and onsite wellness centres that offer comprehensive healthcare at no charge.
The Fortune 100 list was topped by Google. Other entrants include health non-profits Texas Health Resources (31), St Jude’s Children’s Research Hospital (36), Scripps Health (45), Atlantic Health System (46), Children’s Healthcare of Atlanta (56), Southern Ohio Medical Center (61), Mayo Clinic (84), Ohio Health (86), Methodist Le Bonheur Healthcare (92) and Baptist Health South Florida (97).