| Map | Title | Author | Players | |
|---|---|---|---|---|
| UMS Solaris | UMS Solaris | Swordtail | 1 | |
| Unrealupsidedown | UnrealUpsideDown | Rubie For CoopGame | 2-8 | |
| UnrealWorld2 | UnrealWorld2 | THUNDERBOLT | 4-8 | |
| URTechies | UR Techies' Tunnels | Remus Shepherd | Unknown | |
| usp1 | Tarydium caves | Mattias "Uran-238" Ekh | Unknown |