Robe- and mortar-bedecked students during the graduation at Northwestern University in Evanston, Ill. John Kely | The Washington Post | Getty Images

May 29 is 529 day, and with graduation season upon us, it's the perfect time to take a look at the best 529 college savings plans. With nearly every state and the District of Columbia offering at least one 529 plan, investors have dozens of choices, and assets in the plans increased 9.1 percent in 2014 to $249.7 billion, according to College Savings Plan Network. Earnings on contributions are not taxable, nor are withdrawals to pay for qualified higher education expenses. It's important to make sure that the expenses you are covering actually qualify under your 529 plan. (There are special rules for off-campus housing, for example.) You are also limited in how often you can adjust your asset allocation, and some plans come with significant fees. But the tax advantages and the inexorable rise in college costs make 529 plans an attractive option for college savers. Read More529 balances are growing, but so are college costs The following are the top 529 savings plans over the past 10 years that do not require state residency to invest, ranked by savingforcollege.com. -—By Kelley Holland, special to CNBC.com

Posted 28 May 2015

Utah Educational Savings Plan

Turret Arch through North Window at sunrise at Arches National Park, Moab, Utah. Diana Robinson Photography | Getty Images

Investment options in this Utah plan include Vanguard and Dimensional funds, a fixed income fund from the state treasurer and an FDIC–insured account. There are also four age-based investment options, which reallocate assets more conservatively as the beneficiary approaches college age. It scores a 4.9 out of 5 with savingforcollege.com for its reliability, and 3.99 on performance.

New York's 529 College Savings Plan - Direct Plan

Amalgama Photo | Flickr Open | Getty Images

New York's plan uses Vanguard mutual funds and lets investors link their accounts to the Upromise rewards service, which lets users earn cash back for college from participating merchants. The plan charges a low annual asset-based fee of 0.16 percent of account assets. Its performance over 10 years gets 4.61 out of 5 from savingforcollege.com, and its reliability gets a perfect 5. There are static investment options and age-based ones that grow more conservative over time.

Virginia529 inVEST

Richmond, Virginia Bill Dickinson | Moment | Getty Images

The inVEST 529 plan in Virginia offers mutual funds from Vanguard and Parnassus. Investors have a choice of age-based investment options that automatically shift toward conservative assets as college nears, and nine static investment portfolios. It scores 4.1 out of 5 for reliability with savingforcollege.com and 4.06 for costs.

USAA 529 College Savings Plan

Somchaij | Getty Images

As the name suggests, Nevada's 529 plan uses USAA mutual funds. Accounts can link to the Upromise rewards service, which offers cash back for college from participating merchants. Investors can choose an age based investment option or use static investments in different USAA funds. The plan earns a 4.6 out of 5 for reliability and 3.69 for costs.

T. Rowe Price College Savings Plan

A hiker in Palmer, Alaska. Seth K. Hughes | Getty Images

Alaska's nationally branded 529 plan mimics its University of Alaska College Savings Program except for that plan's special features for University of Alaska students. Both use T. Rowe Price funds and offer age-based (or "enrollment-based") investment options that grow more conservative over time, along with static investment options. The nationally branded plan scores 4.8 out of 5 for reliability and 4.59 on performance.

Florida 529 Savings Plan

Miami, Florida Scott B. Smith | Getty Images

Unlike many 529 plans, the Florida 529 Savings Plan uses money management firms to manage its investment pools. Investors can use age-based investment options that grow more conservative as college nears, or static investment options including eight individual investment funds and three pre-designed investment portfolios. The plan scores 4.05 out of 5 for performance.

Ohio CollegeAdvantage 529 Savings Plan

Terrace Park is a village in Greater Cincinnati Swapen Jha | Getty Images

This 529 plan from Ohio offers a wide array of investment options. In addition to three age-based options that grow more conservative as a beneficiary nears college age, there are 14 static investment options using Vanguard funds, two kinds of FDIC-insured deposit accounts, and other static investment options from PIMCO and GE Asset Management. It nets a 4.57 score out of 5 for features and 4.2 for reliability.

College Savings Iowa

Field of Dreams is a 1989 American fantasy-drama film directed by Phil Alden Robinson and is from the novel Shoeless Joe by W. P. Kinsella. Except for a few location shots for Boston, notably Fenway Park, much of the film was shot in Dubuque County, Iowa, and Jo Daviess County, Illinois. Danita Delmont | Getty Images

This Iowa plan features Vanguard mutual funds. Investors can choose age based investment options that shift to more conservative assets over time, or static investment options including 10 individually customizable portfolios and four age-based portfolio options. Accounts can link to the Upromise rewards service, offering cash back for college from participating merchants. The plan scores 4.8 out of 5 for reliability and 4.22 for costs.

College Savings Plan of Maryland – College Investment Pla

Baltimore, Maryland Greg Pease | Getty Images

This 529 plan from Maryland offers 14 different investment options ranging from more aggressive to more conservative investment strategies. You can invest in multiple portfolios, and can also move your investment among portfolios twice per calendar year. The plan scores 4.6 out of 5 for reliability and 3.87 for performance.

Learning Quest 529 Education Savings Plan

Wichita, Kansas Davel5957 | Getty Images