Cat Hill is so named as the incline is constructed predominantly of cats.
Ahem.
Actually, the name Cat Hill may have come from an inn which stood at the bottom of the hill in East Barnet Village. By the 15th century the inn had taken its name from a bridge called Katebrygge, a medieval cattle bridge that crossed the Pymmes Brook.
It was also known as Doggets Hill, after a local landowner.
(Micro cache with a log roll.)
** Congrats to Torists for FTF. Our first Hide was your 1000th Find! :-D