ISO3166

ISO3166, specifically ISO3166-1 alpha-2, is an International Standards Organization standard for two-character country codes. ISO3166 as recognised by the UN and (with exceptions) used for top level domains on the internet.

List of Country Codes

A list of codes for the 246 recognised countries or self-governing territories is as follows: AD,AE,AF,AG,AI,AL,AM,AN,AO,AQ,AR,AS,AT,AU,AW,AX,AZ,BA,BB,BD,BE,BF,BG,BH,BI,BJ,BL,BM,BN,BO,BR,BS,BT,BV,BW,BY,BZ, CA,CC,CD,CF,CG,CH,CI,CK,CL,CM,CN,CO,CR,CU,CV,CX,CY,CZ,DE,DJ,DK,DM,DO,DZ,EC,EE,EG,EH,ER,ES,ET,FI,FJ,FK,FM,FO,FR, GA,GB,GD,GE,GF,GG,GH,GI,GL,GM,GN,GP,GQ,GR,GS,GT,GU,GW,GY,HK,HM,HN,HR,HT,HU,ID,IE,IL,IM,IN,IO,IQ,IR,IS,IT,JE,JM, JO,JP,KE,KG,KH,KI,KM,KN,KP,KR,KW,KY,KZ,LA,LB,LC,LI,LK,LR,LS,LT,LU,LV,LY, MA,MC,MD,ME,MF,MG,MH,MK,ML,MM,MN,MO,MP,MQ,MR,MS,MT,MU,MV,MW,MX,MY,MZ,NA,NC,NE,NF,NG,NI,NL,NO,NP,NR,NU,NZ,OM, PA,PE,PF,PG,PH,PK,PL,PM,PN,PR,PS,PT,PW,PY,QA,RE,RO,RS,RU,RW,SA,SB,SC,SD,SE,SG,SH,SI,SJ,SK,SL,SM,SN,SO,SR,ST,SV,SY,SZ, TC,TD,TF,TG,TH,TJ,TK,TL,TM,TN,TO,TR,TT,TV,TW,TZ,UA,UG,UM,US,UY,UZ,VA,VC,VE,VG,VI,VN,VU,WF,WS,YE,YT,ZA,ZM,ZW

Note that the UK is on "exceptional reserve" for the use by the United Kingdom of Great Britain (GB) and Northern Island and is often used in the place of GB, though the Patent Data Project uses GB.