Here's a list of several online vendors for citrus in the USA (as of April 2014). Many of the vendors are well known and top notch (a few are/were active members of the Citrus Growers Forum), the reliability of others may be questionable. Please feel free to comment regarding your experiences with these (or other) vendors.
If you are uncertain of the vendor, I would recommend contacting them first via email/phone to verify they have the tree you want in stock and that they can ship to your location. The Garden Watchdog (
http://davesgarden.com/products/gwd/#b) is also a good place to check before ordering. Please be aware, there are many Federal restrictions on interstate (and even intrastate) shipment of citrus, if you are in a state with a commercial citrus industry, many of these vendors will not be able to ship trees to you.
Here's the list, in no particular order:
Madison Citrus Nursery
https://madisoncitrusnursery.com/Nursery (Location): Website
Four Winds Growers (California):
https://www.fourwindsgrowers.com/index.phpMckenzie Farms (South Carolina):
http://mckenzie-farms.com/photo.htmHarris Citrus (Florida, approved for out of state shipping):
http://www.harriscitrus.com/store/Brite Leaf Citrus Nursery (Florida, approved for out of state shipping):
http://www.briteleaf.com TreeSource Citrus Nursery (California):
http://www.citrustreesource.comStar Nursery (Louisiana):
http://www.starnurserybellechasse.comNature Hills Nursery (trees from CA?):
http://www.naturehills.com/fruit-bearing/citrus-treesRaintree Nursery (Washington):
http://www.raintreenursery.com/fruit_trees/subtropicals_and_citrus/Logee's Greenhouses (Connecticut):
http://logees.comRolling River Nursery (California):
https://www.rollingrivernursery.com/component/virtuemart/fruit-trees/citrusWoodlanders (South Carolina):
http://www.woodlanders.netEdible Landscaping (Virginia):
http://ediblelandscaping.com/products/tropicals/Citrus/BayFlora (California):
http://bayflora.com/citrustrees.htmlRSI Growers (Arizona):
http://www.rsigrowers.com/citrus/Citrus Trees Online (Texas):
http://www.citrustreesonline.comClifton's Nursery (California):
http://www.buyplantsonline.com/citrustrees.htmlLemonCitrusTree (Citrus Broker, trees from multiple states):
http://lemoncitrustree.com/store/index.php (also selling via Amazon.com)
Larry's Orchids (Citrus Broker???, Michigan):
http://larrysorchids.com/pages/citrus (also selling via Amazon.com)
Petals from the Past (Alabama):
http://petalsfromthepast.com/catalog/index.php?cPath=31_43