| Map | Title | Author | Players | |
|---|---|---|---|---|
| CTF-UdogzOfWar | UDOGZ of War | Hobi-Wan | 4 | |
| CTF-Underground-TDC | CTF-Underground{TDC} | Jeff Smith | 2-16 | |
| CTF-UnderPressure[NC] | UnderPressure | NC|gøkú | 4-12 | |
| CTF-UnderPressureCE[NC] | UnderPressure-ClanEdition | NC|gøkú | 4-12 | |
| CTF-Unearthed | Unearthed City | Chris 'Plutonic' Blundell | 4-8 | |
| CTF-Unearthed | Unearthed City | Chris 'Plutonic' Blundell | 4-8 | |
| CTF-Unearthed_SE | Unearthed City SE | Chris 'Plutonic' Blundell | 4-8 | |
| CTF-Unearthed_SE | Unearthed City SE | Chris 'Plutonic' Blundell | 4-8 | |
| CTF-Unknown | Unknown | Jeremiah 'Byte' Fulbright | 10-12 | |
| CTF-UnrealEd | UnrealEd | Callum "Spiff" Ogden | 2-4 | |
| CTF-UnrealPlaza | Unreal Plaza | Giles Cresswell | 12 | |
| CTF-Uranus | CTF-Unranus | Redeemer99 | 16 | |
| CTF-USS Kobe | USS Kobe | Robert LaPrade | 16 | |
| CTF-UTronic | CTF-UTronic | UTGhost / Ryu_Senshi | 8-14 | |
| CTF-UTronic_Rev | CTF-UTronic_Rev1 | Unknown | 12-16 | |
| CTF-UtterAnnihilation | Utter Annihilation | Tyler "Nestea" Pease | 12-16 |