Look in the phone book for honey, health food, or beekeepers. Sometimes, exterminators will remove hives, give the bees to beekeepers, and sell the honey. University agriculture departments occasionally sell honey. If all else fails, you may have to buy it from the grocery store. The honey will be either raw or processed in some way.
Raw honey has bits of wax, bee parts, dust, pollen, microorganisms, and the like in it.
You have the most control in how you process raw honey, but you also have the most to do. Honey may be filtered, or blended, or even heat-pasteurized to make it clearer and less likely to crystallize. The more processed it is, the milder it is likely to be and the less character it will give to your mead. The processing also dissipates some of the honey's aroma. Crystallized honey is normally acceptable for mead.