1. Usopp's name is possibly based on "Isoppu", which is the Japanese pronunciation of Aesop, the ancient Greek fabulist. Considering that usomeans "lie" in Japanese, the name Usopp can be taken as a portmanteau name between uso and Isopp, since Usopp is both a liar and a storyteller. The name is also a Japanese pun in that saying "Ore wa Usopp!" can mean either "I am Usopp!" or "I am a liar!" because Usopp's name is written using Katakana characters and not Kanji.
2. Usopp's backstory is similar to Aesop's tale The Boy Who Cried Wolf, as he kept calling out that pirates were attacking and so was not believed when pirates actually did come, like the boy when a wolf actually came.
3. It is possible that Usopp's long nose was inspired by the fairy tale "Pinocchio", as Pinocchio was a wooden puppet whose nose grew longer whenever he told a lie.
4. Usopp's birthday, April 1, is known as 'April Fool's Day' a reference to his ability to fool people.Usopp might be somewhat based on the Japanese mythical species tengu, who were said to have long noses and habits of tricking people. Kin'emon even referred to him as a tengu.
5. In regards to his alter-ego, Sogeking is a play on words as the Japanese word for sniper is "Sogeki".
6. Ironically, most of the tall tales and lies he told have come true at some point during the Straw Hats' voyage.
7. Usopp is the only Straw Hat who is not part of the Monster Trio to have awakened Haki.
8. Usopp, Luffy, and Sanji claim to have never fallen ill, and thus do not know what it feels like.
9. Kappei Yamaguchi, Usopp's Japanese voice actor, came up with the notes to the Sogeking song. Oda provided the words and then asked him to develop the notes himself. Kappei also stated that the Sogeking song is the most requested song for him.
10. Skypiea has a theme park dedicated to Usopp called "Rubber Band Land". It has a drawn profile of him on the overhead sign and a statue featuring him as a muscular warrior, complete with a spear.
11. Usopp's occupation in Wano as a toad-oil merchant seems to be a reference to Snake oil, a traditional Chinese remedy without any actual use that became symbolistic for fraud in the West. Ironically, since Wano is based on ancient Japan, the roles would be reversed.
12. Usopp's nose is a little longer than Kaku's.
13. Usopp's favorite foods are pike from an autumn island and other fish of the season.
His least favorite food is mushrooms because he got sick once.
14. Usopp also likes ice cream, the same as Luffy, Chopper, Robin and Brook.
15. Usopp's favorite dish to cook is fish and chips.
16. Usopp's favorite type of island and season is summer on autumn island.
17. Usopp smells like gunpowder.
18. If the Straw Hat Pirates were a family, then Usopp would be the third son.
19.If One Piece was set in the real world, then Usopp would be from Africa.
20. Usopp's thoughts are "Warrior, Lies, Lies, Run, Run", and like the rest of the Straw Hat Pirates, "Friendship".
21. When asked which flower Usopp resembles the most, Nico Robin's japanese voice actress replied he most resembles a daisy.
22. Usopp's blood type is S, the same as Robin's.
23. Usopp bathes once every three days, the same as Chopper and Franky.
24. Usopp and Robin cut the crew's hair.
25. Usopp represents the prefecture of Kanagawa.
26. Usopp typically sleeps at 1:00 A.M. and wakes up at 8:00 A.M.
27. If the Straw Hat Pirates were not pirates, then Usopp would be a graphic designer.
28. If the Straw Hat Pirates had a 50-meter race, then Usopp would come in sixth place.