- Official nickname: "The First State" (it was the first to ratify the Constitution, on Dec. 7, 1787).
- Official state tree: the American holly.
- Official state flower: the peach blossom.
- Official state bird: the "Blue Hen chicken."
From Delaware.gov: "Adopted on April 14, 1939, the Blue Hen chicken had long been used as a motif in numerous political campaigns and in many publications. During the Revolutionary War, the men of Captain Jonathan Caldwell's company, recruited in Kent County, took with them game chickens that were said to be of the brood of a famous Blue Hen and were noted for their fighting ability. When not fighting the enemy, the officers and men amused themselves by pitting their Blue Hen chickens in cockfights. The fame of these cockfights spread throughout the army and when in battle, the Delaware men fought so valiantly that they were compared to these fighting cocks."
- Official state dessert: peach pie.
- Official state fruit: strawberries.
- Official state bug: the ladybug.
- Official state butterfly: the tiger swallowtail (Pterourus glaucus)
- Official state macroinvertebrate: the stonefly (order Plecoptera), said to be an "indicator of the excellent water quality in the state." That is probably true.
From Delaware.gov: "By designating the stonefly as its State macroinvertebrate, Delaware once again demonstrated its leadership as the First State, because currently, no other state in the United States has designated an official State macroinvertebrate." That is certainly not true. A "macroinvertebrate" is just an invertebrate big enough to be seen with the naked eye. That includes most insects, and lots of states have official state insects. In fact, Delaware itself already had at least two (the ladybug and a butterfly) at the time somebody thought it was becoming the first state to designate an official state macroinvertebrate.
- Official state mineral: sillimanite, an alumino-silicate polymorph.
- Official state fish: "the weakfish (Cynoscion genus)," although they probably meant Cynoscion regalis specifically because there are other species in the genus Cynoscion that don't live in the area. Also known, apparently, as the "Bastard trout."
- Official state beverage: milk.
- Official state herb: sweet goldenrod (Solidago odora).
- Official state fossil: belemnite (an extinct squid).
- Official state soil: Greenwich loam, "a coarse, loamy, mixed, semiactive, mesic, Typic Hapludult."
- Official state star: "Delaware Diamond, located in the constellation of Ursa Major (Great Bear)" at RA 9h 40m 44s, dec. 48d 14' 2".
Delaware also claims to be the first state to have designated an official state star. It may be, but I'm not sure the one it designated actually exists. I had trouble finding it in online star catalogs (not that I'm an astronomer). There is no star officially named "Delaware Diamond," that's for sure. Delaware.gov says its star is listed on the International Star Registry, but that's just a company that will take your money to put a listing in a book, like "Who's Who." The International Astronomical Union is the group that officially names space things, and it hasn't named anything "Delaware Diamond."
- Official state marine animal: the horseshoe crab.
- Official state wildlife animal: the grey fox.