The boundaries of Newmarket-Aurora have changed since the last General Election in 2011.

Here is the official description from Elections Canada:

Consisting of that part of the Regional Municipality of York comprised of:

(a) the Town of Newmarket;
(b) that part of the Town of Aurora lying northerly of Wellington Street West and Wellington Street East; and
(c) that part of the Town of East Gwillimbury lying southerly of Green Lane West and Green Lane East and westerly of Highway No. 404.