Muswell Hill is an area of North London. It's a quite nice, dull, middle class area inhabited by media types and Guardian readers. Probably its most notable feature is Alexandra Palace. Will Self lives there (in Muswell Hill I mean, not in Alexandra Palace).
Although it has five pubs (or more depending on where you stop counting), two of them are awful and the other three are souless 'Oirish pub' chains. The John Baird used to be good but it's just re-opened after refurbishment and become Oirish. It might still be good though, I haven't been back yet.
The name is a corruption of 'Mossy well on the Hill', there was also a river Moss, but it's now just a stream that runs through my friend's back garden and makes his lawn into a swamp.
It's quite a big hill. The steepest bit is the road called 'Muswell Hill'. I've cycled up it once, and I only just managed it.