I would check Latin markets, especially the bigger ones. Look for naranja agria

I order them from Ripe To You, a ranch in California, but they are now out of season. Sorry I am late seeing this. If you are interested for next year, the website is https://ripetoyou.com/shop/

Balduccis maybe. Wegmans might be willing to special order if you ask the manager. That way you'd save on shipping.

I think i have seen these at Whold foods, but my brain could be playing tricks on me.

You will have to order them from a grower. I have never seen sour oranges at any grocer in the DC area.

Been a while.

I have never seen them in a store here, only in California. You can buy them online from specialty vendors.

They may be listed under a different name... also called bitter orange, sour orange, bigarade orange, or marmalade orange

My understanding is this is the season for them and I have a tart recipe I want to try. My local Whole Foods had none, and didn’t know if/when they might get some, and my local Safeway had never heard of them.