First of all - every 529 account in the country is run by some state treasury department. Even branded 529 accounts like a Raise Education account, are technically set up with a treasury department in some US state. It's worth noting, however, that the state you choose for your 529 account doesn't matter too much. For example: you can live in Tennessee, have an account in Utah, and your child can attend UCLA in California... and still use the 529 funds.
We create all of our accounts with My529 - Utah's 529 account provider. We've been very impressed with the performance and flexibility of Utah's 529 accounts, as well as their software platform.