New York. The closest I have been is Beech Grove, Indiana.
I’ve never been to Houston, San Antonio, San Diego, San Jose, or Jacksonville, but otherwise, I’ve been to all the cities in the top 15, and I’ve actually lived in three of them, although I only “lived” in Chicago for 10 weeks, when I was on an extended visit with some family.
I was very surprised that Indianapolis is number 12. It doesn’t seem that big. Wiki must be counting all the incorporated townships and Speedway, not just Indianapolis proper.
Indianapolis consists of the entire territory of Marion County, except for the small incorporated towns like Speedway, Beech Grove, and Lawrence.
Looking at this list the largest New Zealand town I haven’t been to is Pukekohe (27,300). I would have guessed Whakatane but that’s only 18,950.
In the UK, Birmingham, which is second largest, I believe. I once bought petrol on the outskirts, somewhere, but I don’t think that counts. I do not really feel I have missed out much. I never heard of anybody who wanted to go to Birmingham, and I can’t think of any"attractions" to see there.
Honestly, I need to use a list to figure this one out. I have been to pretty much every big town Canada has.
Now, if you go by municipal borders, I believe I have never set foot in Surrey, BC. Surrey is part of the urban agglomeration most would just call “Vancouver” but it’s technically a different city so there’s mine.
In terms of actually being its own city, I’ve not yet been to Sherbrooke.
I’ve never been to Chicago which is the 3rd largest city in the US. I’ve also never been to Juneau; which is the largest city in the US by area.
What about Perth?
If you count Tokyo’s 23 wards as a single city, Nagoya (2.2m) is the 4th largest city in Japan and I’ve never been there. I’ve been through it a few times, but I’ve yet to have a chance to actually visit. It’s high on my list though.
If you consider traveling through on a train as “being to” a city, then I would have to say Sapporo (1.9m, next largest after Nagoya). I’ve yet to visit the island of Hokkaido at all. I really need to start traveling again.
The largest U.S. city I know for certain I’ve never been to is Corpus Christi, TX (#60).
Not sure about others like Virginia Beach, VA or Raleigh, NC or Tulsa, OK – I’d have to verify with someone who would know. Others like Columbus, OH and Jacksonville, FL I know I’ve been to but have no memory, since I was too young to remember or passed through on a bus at night.
The largest Canadian city I’ve never visited is Ottawa – other than that I’ve filled out the top ten.
It’s either Brampton, Ontario (#9, according to Wikipedia), or Hamilton, Ontario (# 10).
Brampton is part of the extended metro area around Toronto, so I’m not sure if I’ve ever been there. I know I’ve only driven through Hamilton, without stopping.
Me too. Also missed out on Phoenix, San Diego and Dallas (6th, 8th, and 9th in the top ten).
Sydney #1
Melbourne #2
Brisbane #3
Newcastle #7
Canberra #8
Wollongong #10
Geelong #12
#3 Brisbane. Hopefully to be rectified soon.
For sure: re England and Wales on the LoveMyTown list, Liverpool is third in population – after only London and Birmingham; Cardiff is tenth.
Oh, my ! For that, you’d be in danger of having a fair number of the just over 1 million inhabitants of Birmingham, baying for your blood… I live in Birmingham myself, though from force of circumstances, rather than from choice. It does have the Jewellery Quarter – fascinating area where the making of jewellery was and to some extent is, concentrated, including a very interesting museum set in an old-fashioned factory for that purpose; the Balti Triangle (an in itself rather scruffy area which contains what is usually reckoned Britain’s best concentration of restaurants serving Pakistani / North Indian food); the Thinktank (an ingeniously set up science museum / centre, particularly focused on making science accessible to children); an assortment of other fine museums and art galleries; a splendid and venerable Botanical Gardens; it’s threaded by canals made some 200 years ago, fascinating if one likes that sort of thing; and it has a National Sea Life Centre – seems a bit crazy, in the city which in all of Britain, is furthest from the sea; but there you are. And reputedly, great shopping and nightlife.
Vancouver I guess. 
Of the top 5 in the US, I’ve not been to LA or Houston. Born and raised in NY, so that was a gimme. And who doesn’t go to Philly from NY for a day? And it was actually The Straightdope that got me to Chicago. That was a fun time.
San Antonio is the largest city in the US I’ve never been to. That and Jacksonville are the only two in the top 15 that I’ve never visited.
I’ve pretty much coloured in all the key towns and cities of NI and Scotland, but have lived in England now for just over 4 years and still have a lot of places to visit. I’ve covered a quite a lot, as we live in the midlands and like our local weekends away for sightseeing and cycling, so would expect I’ve seen more than most locals by now. But despite a week in Yorkshire for Le Tour this July, I’ve still not made it to Leeds. (comes in at number 8).
Although, only Bolton (30), Southend (35), Warrington (39) and Birkenhead (50) remain unvisited from the top UK 50 cities, so not too shabby for getting about.
While making disparaging comments on cities can – as mentioned upthread – be potentially risky: I think most Britons would be of the opinion that as regards Birkenhead, you’re not missing a great deal. Generally reckoned one of the country’s less interesting or appealing cities. This due in part, I think, to Birkenhead’s having long been overshadowed by its bigger, better-known, and more glamorous counterpart Liverpool, just on the other side of the Mersey estuary (Liverpudlians have traditionally dubbed Birkenhead, “The One-Eyed City”). Birkenhead has for long been characterised thus, by an acute inferiority complex: its inhabitants reckoned as tending to be surly and unwelcoming to outsiders, and fiercely proud of their town, on the principle of “no man loves his city because it is great; but because it is his”.