Now called Shamrock Foods Federal Credit Union to match the company's current name, Shamrock Foods Company – the umbrella company for the dairy and the food products distributor Shamrock Foods – the credit union now serves employees of the company and its subsidiaries, as well as their family members. Shamrock Foods FCU has around 1,400 members living primarily in Arizona, Colorado, New Mexico and Southern California.

2. Arkansas AM & N College Federal Credit Union (Pine Bluff, Ark., $2.28 million)

The name of this credit union's founding college may have changed, but the credit union's hasn't. The credit union was started by a group of employees from Arkansas Agricultural, Mechanical & Normal (AM & N) College, now the University of Arkansas at Pine Bluff, in 1952, when "it was difficult, if not impossible, to get a loan from any of the financial institutions in the city," the credit union said.

The historically African American university opened in 1873 as the Branch Normal College and operated as a division of the University of Arkansas. In 1927, the college gained independence from the University of Arkansas and became Arkansas AM & N College. It rejoined what is now called the University of Arkansas System in 1972 and earned its current name. Arkansas AM & N College FCU now serves around 950 university employees, alumni and their families.

3. Yellowstone Federal Credit Union (Yellowstone National Park, Wyo., $5.06 million)

The founders of this credit union spent most of their days at the site of Old Faithful and a handful of the world's other geysers – Yellowstone Federal Credit Union was chartered in 1937 to provide permanent employees of the National Park Service in Yellowstone National Park access to credit, the credit union said.

Since 1972, the 1,100-member Yellowstone FCU has been open to all employees of the National Park Service in Yellowstone National Park, as well as residents of Yellowstone National Park, Wyo., Gardiner, Mont. and a southern section of Montana's Paradise Valley.

4. Credit Union One (Fond du Lac, Wis., $5.7 million)

Machinery manufacturing runs deep in the history of this credit union, chartered in 1964. It was originally named Fond du Lac Machine Employees Credit Union and served the employees of Giddings & Lewis Inc., a machine shop founded in 1859 that supplied local sawmills and malt mills (hence, a credit union named for machine employees who lived in Fond du Lac, Wis.)

In 1967, the credit union's name changed to G&L Employees Credit Union, and in 2005 – the same year a number of machine tool engineering companies, including Giddings & Lewis, came together to form the global manufacturing company MAG – it became Credit Union One. The 900-member credit union now welcomes anyone who lives or works in Wisconsin's Fond du Lac County.

5. C.U.P. Federal Credit Union (Provo, Utah, $6.5 million)

The initials "C.U.P." stand for the Central Utah Project (a federal water project introduced in the 1950s allowing the state to utilize a portion of the Colorado River) and signify the credit union's original members. It opened in 1960 to serve employees of the U.S. Bureau of Reclamation – which oversees water resource management in the country – who were working on the C.U.P.

Now, the 1,300-member C.U.P. FCU is open to employees and family members of the U.S. Bureau of Reclamation as well as four other utilities-related groups: the Strawberry Water Users Association, the South Utah Valley Electrical Service District, the Central Utah Water Conservancy District and the Uintah Water Conservancy District.

6. Glacial Lakes Education Employees Federal Credit Union (Watertown, S.D., $1 million)

Education is central to the history of this Watertown, S.D.-based credit union, which opened in 1954 as Watertown Faculty Federal Credit Union. In 1981, its name changed to Watertown Educational Employees Federal Credit Union and membership expanded to include employees of the Watertown School District and their family members.

Nearly two decades later, the 280-member credit union is open to employees and family members of eight additional South Dakota school districts – hence its most recent name change to Glacial Lakes Education Employees Federal Credit Union, which represents the glacial lakes and prairies region located in the northeastern part of the state.

7. Bi-Mart Federal Credit Union, (Eugene, Ore., $6.8 million)

This 2,300-member credit union serves the employee-owned Northwest chain retailer Bi-Mart. Bi-Mart Federal Credit Union first opened its doors in 1969.

The Eugene, Ore.-based Bi-Mart requires a membership to shop, has locations in Oregon, Washington and Idaho, and offers discounted merchandise including foods, electronics, toiletries, outdoor gear and small appliances.

One of its unique attributes is "Lucky Number Tuesday" – a weekly in-store event that gives shoppers the chance to win prizes by matching their membership numbers to a membership number chosen randomly by the store.

8. Island Tradition Federal Credit Union (Honolulu, $3 million)

This 600-member Hawaii credit union's history also centers on retail. It was founded in 1937 as Libhouse Employees Federal Credit Union and served the employees of Liberty House, a department and specialty store chain with locations in Hawaii and Guam, the credit union said.

The national chain Federated Department Stores later purchased Liberty House, and at that time, the credit union was renamed Island Tradition Federal Credit Union. Since then, it has served employees of the department store giant Macy's in Hawaii and Guam, as well as their family members.