London Borough of Watford

My first proposed borough is centred around the town of Watford currently in Hertfordshire. The boundaries of this borough is basically the three Hertfordshire districts of Watford, Three Rivers and Hertsmere. Pictured below is the actual potential borders. Note the alignment to motorways in many places as well as going outside the M25 in places to encompass the towns of Potters Bar and Chorleywood. I estimate this borough would have a population of 280,000.

Towns and villages included in the Borough:

Watford, Borehamwood, Elstree, Bushey, Radlett, Shenley, South Oxhey, Rickmansworth, Maple Cross, Denham Green, Chorleywood, Potters Bar

Notable things about the area:

Borehamwood and Elstree are the site of a number of famous film studios collectively known as Elstree studios.
A number of the smaller towns have large percentages of their populations being Jewish. In particular Radlett is almost 30% Jewish and the most Jewish built-up area in the country.
The Three Rivers district was the second most peaceful local authority according to this.
Watford FC.
The Warner Bros. Studio Tour - London is in Watford.