Very big. Technically big enough to be a city, but we haven't got a cathedral, so we're not.
Has its own tube station, which will soon be closed if they go ahead with the Croxley Rail Link project. But it will be replaced with TWO stations, yes TWO - Ascot Road (the post sorting office) and Hospital.
Lots of places in the UK end with -ford. This is (not) because they are home to Ford dealerships. Watford has many, and therefore you must decide "Wat ford? (shall i visit) ", which is where it (doesn't) get its name.