Which city's population is larger Halifax Canada or Halifax UK?

To answer that...

The population of Halifax, England as of 2004 is...

City: ~82,500

Metro (Calderdale): ~200,000

The population of Halifax, Nova Scotia as of 2006 is...

City: ~285,000

Metro (H.R.M.): ~410,000

So, Halifax, Nova Scotia is bigger than Halifax, England.