Yes, and for about 26 years (1901-1927) it was the capital of Australia.
London
Vienna
Tel Aviv
USA:
Boston
Denver
Hartford
Annapolis
Santa Fe
Providence
Salt Lake City
Washington, DC
National:
Washington
Ottawa
San Jose CR
London
Paris
Helsinki
Moscow
Seoul
Taipei
Georgetown, Cayman Islands
Territorial:
Hamilton, Bermuda
Hong Kong
US State:
Most, not gonna list 'em all
Provincial:
Toronto
Saint John
Halifax
Thanks! I don’t suppose I can really claim to have visited the capital of Australia, then, as I seem to have been about 70 years too late.
London
Canberra
Edinburgh (if Scotland counts as a country)
Washington, DC
Sacramento, CA
Columbus, OH
Boston, MA
Atlanta, GA
Harrisburg, PA (airport to get to Lancaster)
Providence, RI (airport to get to New London, CT)
Denver, CO (flight stopover)
Honolulu, HI (flight stopover)
Almost forgot non-USA state/provincials:
Sydney (New South Wales)
Melbourne (Victoria)
Victoria (BC)
London
Paris
Brussels
Amsterdam
Berlin
Copenhagen
Prague
Vienna
Bern
Ljubljana
Bratislava
Budapest
Warsaw
Vilnius
Riga
Tallinn
Helsinki
Bucharest
Sarajevo
Skopje
Belgrade
Tirana
Sofia
Valletta
Moscow
Tbilisi
Yerevan
Tiraspol
Athens
Ankara
Damascus
Beirut
Amman
Kuwait City
Doha
Abu Dhabi
Muscat
Sana’a
Tehran
Ashgabat
Tashkent
Tunis
Khartoum
Addis Ababa
Kampala
Kigali
Hargeisa
Taipei
Bangkok
Phnom Penh
Vientiane
Beijing
Tokyo
Seoul
Pyongyang
Canberra
Wellington
Plus about 25 US state capitals.
Alphabetical by country:
Algiers
Andorra la Vella
Vienna
Dhaka
Brussels
Belmopan
Porto Novo/Cotonou
Sucre/LaPaz
Sarajevo
Gaberone
Sofia
Ouagadougou
Yaounde
Ottawa
Santiago
Bogota
Moroni
San Jose
Zagreb
Nicosia
Copenhagen
Quito
Cairo
San Salvador
Helsinki
Paris
Libreville
Banjul
Berlin
Bonn (then)
Accra
Guatemala City
Tegucigalpa
Budapest
Tehran
Dublin
Jerusalem (Israel)
Abidjan
Amman
Nairobi
Seoul
Kuwait City
Vientiane
Beirut
Maseru
Montovia
Tripoli
Vaduz
Vilnius
Luxembourg City
Skopje
Antananarivo
Lolongwe
Bamako
Valetta
Nouakchott
Port Louis
Mexico City
Podgorica
Rabat
Windhoek
Katmandu
Amsterdam/The Hague
Managua
Lagos (then)
Oslo
Jerudalem (Palestine)
Panama City
Asuncion
Lima
Warsaw
Lisbon
Bucharest
Kigali
Dakar
Belgrade
Freetown
Singapore
Bratislava
Ljubljana
Pretoria/Cape Town
Madrid
Khartoum
Mbabane
Stockholm
Damascus
Dodoma/Dar es Salaam
Bangkok
Lome
Tunis
Kampala
Abu Dhabi
London
Washington
Montevideo
Caracas
Hanoi
Lusaka
Harare
Unrcognized countries or other entities)
Pristina
Nicosia
Taiwan
Willemstaat
Gibraltar
Victoria (HK)
Macao
St. Pierre
Washington D.C.
London
Paris
Berlin
Bonn (was the capital at the time)
Luxembourg City
Brussels
Dublin
Hamilton Bermuda
Kuwait City
Baghdad
Zurich
Reykjavik (stopover only)
Bucharest (stopover only)
States? Lets see if I remember.
Trenton
Albany
Hartford
Boston
Annapolis
Richmond
Austin
Atlanta
Nashville
Columbus
Harrisburg
That’s all that is coming to me at the moment. I’ve been to a lot more states but don’t remember spending any time in their capitals.
My above list of national capitals, plus 47 in USA (except Phoenix, Honolulu, Juneau), ten in Canada, 28 in Mexico, and in incalculable and ungodly number of state, provincial, and departmental capitals in other countries.
Denver is not a state capital. Stop listing it as one, all of you.
Oops. Delete that and add Vatican City. At least I didn’t list Istanbul.
What do you think is the capital of Colorado? Look at Wikipedia Colorado State Capitol please.
I think a more interesting poll would be which Capitol Buildings have you visited? Just being in the city is no more interesting than being at the city’s airport.
When I visited the city, I saw the Colorado State Capitol there. If it’s not the capital of Colorado, it’s doing a very good imitation of one. So what is the capital of Colorado?
For capitals outside the U.S., other buildings might qualify as symbolising the status of being a capital, e.g., the royal palace, or the office building where the president or prime minister works. For example, for London, I think Buckingham Palace or 10 Downing Street would count just as much as Parliament House. (I’ve been just outside all three, but inside none of them.)
I’ll figure out US state capitals later (it’s almost time to go home!)
National:
Washington
San Jose, Costa Rica
Jerusalem
Beijing
Lima
Paris
London
Amsterdam
Brussels
Washington DC
Tokyo
Manila
Edinburgh
Lisbon
Al-Manama
Ljubljana
Lansing MI
Indianapolis IN
Des Moines IA
Boston MA
Providence RI
Honolulu HI
Richmond VA
Olympia WA
Hartford CT
Annapolis MD
Albany NY
Madison WI.
San Juan PR
Agana GU
Halifax NS
Seven nations (eight if I can count British Hong Kong), 12 US states, two US territories, and one Canadian province.
As I mentioned in the other thread, it depends if you count my standing on the side of the road with my thumb out. If so, I’ve been to the capitals of all the 49 states I’ve been in, and also the national capital. If not, maybe half or a little more, and still also D.C.
Canadian provinces (with the same caveat): Quebec, Toronto, Winnipeg, Regina, Edmonton, and the national capital of Ottawa.
National capitals outside the U.S. and Canada, not much:
Rome, Vatican City (And yes, I did hitchhike in Italy too, but only from Catania to Messina. The trip to Rome and V.C. was separate. 
)
This is some kind of joke I’m not getting, right? Denver became the capital while Colorado was still a territory.
Two national capitals: Ottawa and Washington (Canada and the United States are the only two countries I’ve ever been in).
State capitals: Definitely Albany, Atlanta, Baton Rouge, Boston, Columbia, Columbus, Harrisburg, Hartford, Jackson, Little Rock, Montgomery, Montpelier, Raleigh, Richmond, and Trenton and maybe Annapolis, Augusta, Charleston, Concord, Dover, Frankfort, Providence, and Tallahassee.
Provincial capitals: Charlottetown, Fredericton, Halifax, Quebec, and Toronto.
It’s an internet meme that Denver isn’t really the capital of Colorado.