| Ancaster—Dundas— Flamborough—Westdale | |
| Province: | Ontario |
| Prov-Status: | defunct |
| Prov-Created: | 2004 |
| Prov-Abolished: | 2015 |
| Prov-Election-First: | 2007 |
| Prov-Election-Last: | 2014 |
| Prov-Rep: | Ted McMeekin |
| Prov-Rep-Party: | Liberal |
| Demo-Census-Date: | 2006 |
| Demo-Pop: | 111844 |
| Demo-Electors: | 82367 |
| Demo-Electors-Date: | 2007 |
| Demo-Area: | 744 |
| Demo-Cd: | Hamilton |
| Demo-Csd: | Hamilton |
Ancaster—Dundas—Flamborough—Westdale was a provincial electoral district in southwestern Ontario, Canada. It was created for the 2007 provincial election. 82.9% of the riding came from Ancaster—Dundas—Flamborough—Aldershot while 17.1% came from Hamilton West.
The riding included all of Hamilton west of a line running along Glancaster Road then to Garner Road then to a Hydroelectric Transmission Line then to Highway 403 to Hamilton Harbour.
In 2018, the district was dissolved into Hamilton West—Ancaster—Dundas and Flamborough—Glanbrook.
| 2007 Ontario electoral reform referendum | ||||
|---|---|---|---|---|
| Side | Votes | % | ||
| First Past the Post | 30,716 | 63 | ||
| Mixed member proportional | 18,033 | 37 | ||
| Total valid votes | 48,749 | 100.0 | ||