Avalon

StatCan's Census Division 1 is, very handily, the Avalon peninsula.

All it took was a bit of math and the handy map breakdown of census subdivisions and municipalities to produce this:

St. John's Census Metropolitan Area: 181,113 (this includes Mount Pearl, CBS, Paradise, etc)
Northern Avalon (excluding the above): 56,440
Southern Avalon: 10,865

The St. John's CMA contains 72.9% of the Avalon's entire population, the rest of the northern Avalon is 22.7%, and the southern Avalon is 4.3%.

It is also notable that Bay Roberts is a Census Agglomeration; that is to say, more than 10,000 people live around its urban core. It achieved this for the first time in the 2006 census. There are only 4 such in the entire province (the others are Corner Brook, Grand-Falls-Windsor, and St. John's itself).

The largest settlements in the southern Avalon are Placentia (3,898), Trepassey (763), Cape Broyle (545), Ferryland (529)