ÂLAND ISLANDS- OH0
ALASKA (USA State) - AL, WL
ANDORRA - C3
ANGUILLA - VP2E
ANTIGUA & BARBUDA - V2
ARUBA - P4
ASCENCION ISLAND - ZD8
AZORES - CU
BAHAMAS - C6, VP7
BAHRAIN - A9
BARBADOS - 8P
BERMUDA - VP9
BRITISH VIRGIN ISLANDS - VP2V
BRUNEI DERUSSALAM - V8
CANARY ISLANDS - EA8-EH8
CAPE VERDE - D4
CAYMAN ISLANDS - ZF
CEUTA - EA9-EH9 (Shares callsign prefix with Melilla)
CHECHNYA* - 1B, 1X (Both Unofficial: 1B is also used by Turkish Republic of Northern Cyprus)
CHRISTMAS ISLAND - VK9X
COCOS-KEELING - VK9C
COMOROS ISLANDS - D6
CYPRUS - 5B, C4, H2, P3
(UK Sovereign Bases on Cyprus - ZC4)
DANZIG - YM4 (Deleted After German Invasion)
DOMINICA - HI
EAST TIMOR - See TIMOR LESTE
FALKLAND ISLANDS - VP8/F
FAROE ISLANDS- OY
FIJI - 3D2, VR2
FRENCH POLYNESIA - FO
GAMBIA, THE - C5
GIBRALTAR - ZB2
GRENADA - J3
GUADELOUPE - FG
HAWAI'I (USA State) - AH6, AH7, KH6, KH7, NH6, NH7, WH6, WH7
HONG KONG S.A.R. - VR
ICELAND - TF
ISLE OF MAN - See MAN, ISLE OF
JERSEY - GH, GJ
KIRIBATI - T3
LEBANON - OD
LESOTHO - 7P
LIECHTENSTEIN - HB0
LUXEMBOURG - LX
MACAO S.A.R. - XX9
MALDIVES - 8Q
MALTA (Republic) - 9H
MALTA, SOVEREIGN MILITARY ORDER OF - See SOVEREIGN MILITARY ORDER OF MALTA
MAN, ISLE OF - 2D, GD, GT, MD, MT
MARSHALL ISLANDS - V7
MAURITIUS - 3B8
MELILLA - EA9-EH9 (Shares callsign prefix with Ceuta)
MICRONESIA - V6
MAYOTTE - FH
MONACO - 3A
MONTSERRAT - VP2M
(Mount Athos Monestary, Greece) - SV2A
NAURU - C2
NETHERLANDS ANTILLES - PJ2, PJ4, PJ9
NIUE - ZK2
NORFOLK ISLAND- VK9N
PALAU - T8
PALESTINE - E4
PITCAIRN ISLANDS - VP6, VR6
QATAR - A7
SAINT HELENA - ZD7
SAINT KITTS & NEVIS - V4
SAINT LUCIA - J6
SAINT PIERRE & MIQUELON - FP
SAINT VINCENT & THE GENADINES - J8
SAMOA, INDEPENDENT STATE OF - 5W
SAN MARINO - T7
SAO TOME & PRINCIPE - S9
SCOTLAND (ALBA) - 2M, GM, GS, MM, MS
SEALAND* - 1SL, S1 (Both Unofficial)
SEBORGA* - 1P, T0 (Both Unofficial)
SEYCHELLES - S7
SINGAPORE - 9V
SOVEREIGN MILITARY ORDER OF MALTA - 1A0 (Unofficial)
SPRATLY ISLANDS - 1S (Unofficial) (Islands claimed by Malaysia use "9M".)
SWAZILAND - 3DA, ZD5
TIBET - AC4, AC5 (Deleted Since Chinese Invasion)
TIMOR LESTE (East Timor) - 4W
TOKELAU - ZK3
TONGA - A3
TRINIDAD & TOBAGO - 9Y
TRISTAN DA CUNHA - ZD9
TURKISH REPUBLIC OF NORTHERN CYPRUS* - 1B (Unofficial: Also used by Chechnya)
TURKS & CAICOS - VP5
TUVALU - T2
UNITED STATES OUTLYING ISLANDS & TERRITORIES
AMERICAN SAMOA - KH8, WH8
ANTARCTIC BASES - KC4
BAKER & HOWLAND ISLANDS - NH1
DESECHEO ISLAND - KP5, NP5, WP5
EAST CAROLINE ISLAND - NC6/E
GUAM - AH2, KH2, NH2, WH2
GUANTANAMO BAY, CUBA - KG4
JOHNSTON ISLAND (Now Closed) - AH3, KH3, NH3, WH3
KINGMAN REEF - AH5K, K5K, KH5K, NH5K, WH5K
KURE ISLAND - AH7K, KH7K, NH7K, WH7K
MARIANA ISLANDS - AH0, KH0, NH0, WH0
MIDWAY ISLAND - AH4, KH4, KM6, NH4, WH4
NAVASSA ISLAND - KC4, KP1, WP1
PALMYRA & JARVIS ISLANDS - AH5, NH5, WH5
PUERTO RICO - KP3, KP4, NP4, WP4
SWAINS ISLAND - N8S
UNITED STATES VIRGIN ISLANDS - WP2
WEST CAROLINES - AC6, NC6/W
WAKE ISLAND - AH9, NH9, WH9
VANUATU - YJ
VATICAN CITY - HV
WALES (CYMRU) - 2W, GC, GW, MC, MW
WALLIS & FUTUNA - FW
WESTERN SARAHA - S0
NON-GOVERNMENTAL ORGANIZATIONS
International Civil Aviation Organization [ICAO] - 4Y
United Nations [UN] - 4U
International Telecommunications Union, Geneva, Switzerland - 4U_ITU
United Nations Headquarters, New York City, NY, USA - 4U_UN
United Nations Offices, Vienna, Austria - 4U_VIC
World Bank, Washington, DC, USA - 4U_WB
World Meteorological Organization [WHO] - C7
*Chechnya, Sealand, Seborga and the Turkish Republic of Northern Cyprus (TRNC) are not recognized by the Amateur Radio Relay League (ARRL) as DXCC entities, while the Sovereign Military Order of Malta (SMOM) and the Spratly Islands are, despite the useage of an unofficial prefix.
If there are any callsigns/nations I missed (or if anyone knows if Trans-Dniester has begun issuing amateur licenses with their own callsign prefix), let me know.