Nations independent of the URE but are allies:
Confederacy of the United Systems (confederal, parliamentary republic; POP: 13,784,122,578 billion citizens) [9 planetary (major) colonies/17 planetary (minor) colonies/34 lunar colonies/35 colony platforms]
Republic of Sephora (parliamentary republic; POP: 248,790,319 million citizens) [5 planetary (major) colonies/13 planetary (minor) colonies/4 lunar colonies/21 colony platforms]
Federation of the Culan Sector (federal, representative democracy; POP: 8,874,421,911 billion citizens) [13 planetary (major) colonies/28 planetary (minor) colonies/38 lunar colonies/76 colony platforms]
United Federation of New Victoria (federal, parliamentary democracy and constitutional monarchy; POP: 12,437,199,554 billion citizens) [1 planetary (major) colony/12 planetary (minor) colonies/23 lunar colonies/46 colony platforms]
Union of Independent Colonies (representative, presidential republic; POP: 3,617,203,834 billion citizens) [13 planetary (major) colonies/26 planetary (minor)/17 lunar colonies/74 colony platforms]
United Federation of Chorus (federal, parliamentary republic; POP: 408,268,098 million citizens) [12 planetary (major) colonies/17 planetary (minor) colonies/48 lunar colonies/52 colony platforms]
Republic of Venezia (presidential republic; POP: 12,436,109 million citizens) [5 planetary (major) colonies/6 planetary (minor) colonies/21 lunar colonies/28 colony platforms]
Vytal Federation (federal, parliamentary republic; POP: 3,131,774,698 billion citizens) [28 planetary (major) colonies/32 planetary (minor) colonies/56 lunar colonies/45 colony platforms]
Osea I system [Independent: 6 planetary (major) colonies/8 planetary (minor) colonies/56 lunar colonies/98 colony platforms]
*Osean Federation (federal, presidential, constitutional republic; POP: 2,613,788,023 billion citizens)
*Federal Republic of Belka (federal, parliamentary, constitutional republic; POP: 473,568,109 million citizens)
*Commonwealth of Fato (parliamentary republic; POP: 1,776,445 million citizens)
*Wielvak Republic (federal republic; POP: 23,135,451 million citizens)
*Republics of the Nordlands (parliamentary democracy; POP: 1,782,109 million citizens)
*Democratic Federation of Wellow (constitutional federation; POP: 23,876,342 million citizens)
*Commonwealth of Ratio (parliamentary republic; POP: 1,456,233 million citizens)
*Kingdom of Sapin (constitutional monarchy and representative democracy; POP: 2,367,889 million citizens)
*Republic of Ustio (constitutional republic; POP: 12,765,231 million citizens)
*Commonwealth of Recta (federal, parliamentary republic; POP: 6,543,122 million citizens)
*Kingdom of Gebet (federal democracy and constitutional monarchy; POP: 2,148,987 million citizens)
Osea II system [Independent: 7 planetary (major) colonies/5 planetary (minor) colonies/4 lunar colonies/15 colony platforms]
*Democratic Republic of Leasath (constitutional republic; 11,771,835 million citizens)
*Federal Republic of Aurelia (federal, presidential republic; 13,563,442 million citizens)
Verusa system [Independent: 5 planetary colonies/15 lunar colonies/26 colony platforms]
*Union of Yuktobanian Republics [Yuktobania] (supranational union styled as a parliamentary republic; POP: 1,231,567,984 billion citizens)
*Republic of Verusa (constitutional republic; POP: 562,781,342 million citizens)
*Republic of Sotoa (federal, presidential republic; POP: 678,215,783 million citizens)
*Republic of Kaluga (federal republic; POP: 12,556,861 million citizens)
*Commonwealth of Romny (parliamentary republic; POP: 233,988,104 million citizens)
Anea system [Independent: 3 planetary colonies/19 lunar colonies/28 colony platforms]
*Republic of Emmeria (liberal, constitutional republic; POP: 16,881,207 million citizens)
*Federal Republic of Estovakia (federal republic; POP: 16,712,346 million citizens)
*Kingdom of Nordennavic (constitutional monarchy and federal democracy; POP: 12,653,848 million citizens)
Usea system [Independent: 5 planetary colonies/27 lunar colonies/36 colony platforms]
*Republic of North Point (liberal democracy; POP: 13,356,781 million citizens)
*Commonwealth of San Salvacion (federal, presidential republic; POP: 2,513,826 million citizens)
*Federal Republic of Erusea (federal republic; POP: 565,453,098 million citizens)
*Republic of Amber (constitutional republic; POP: 167,284,563 million citizens)
*Republic of Delarus (parliamentary republic; POP: 327,146,198 million citizens)
*Federal State of Ugellas (federal republic; POP: 89,562,234 million citizens)
Draco 56 system [Independent: 1 planetary (major) colony/2 planetary (minor) colonies/9 lunar colonies/18 colony platforms]
*New Hong Kong Federation (federal parliamentary, presidential republic; POP: 11,837,529,460 billion citizens)
Sagittarius Indi system [Independent: 1 planet (major) colony/5 (minor) colonies/13 lunar colonies/24 colony platforms]
*United Republic of Anio (representative democracy; POP: 15,732,048,966 billion citizens)
AN: The Independent Sectors/Colonies are considered to be independent of the URE, yet they are still are members, albeit honorary, this is considered to be extremely AU. Did you notice the Ace Combat references too?
The URE, by 2564, has the largest population of human-controlled territory with 40 billion citizens.