| Province: | Ontario |
| Leeds—Grenville—Thousand Islands and Rideau Lakes | |
| Prov-Status: | active |
| Prov-Created: | 1986 |
| Prov-Election-First: | 1987 |
| Prov-Election-Last: | 2022 |
| Prov-Rep: | Steve Clark |
| Prov-Rep-Link: | Steve Clark (Canadian politician) |
| Prov-Rep-Party: | PC |
| Demo-Census-Date: | 2016 |
| Demo-Pop: | 100545 |
| Demo-Electors: | 82511 |
| Demo-Electors-Date: | 2018 |
| Demo-Area: | 3747 |
| Demo-Cd: | Leeds and Grenville |
| Demo-Csd: | Athens, Augusta, Brockville, Edwardsburgh/Cardinal, Elizabethtown–Kitley, Front of Yonge, Gananoque, Leeds and the Thousand Islands, Merrickville–Wolford, North Grenville, Prescott, Rideau Lakes, Westport |
Leeds—Grenville—Thousand Islands and Rideau Lakes is a provincial electoral district in Ontario, Canada, that has been represented in the Legislative Assembly of Ontario since 1987. Before the 2018 election, it was known simply as Leeds—Grenville.
It consists of the United Counties of Leeds and Grenville.
Since 1999, provincial ridings have been defined to have the same borders as federal ridings.
For the 2018 election, the district gave up a small portion of territory to Lanark—Frontenac—Kingston.
| 2007 Ontario electoral reform referendum | ||||
|---|---|---|---|---|
| Side | Votes | % | ||
| First Past the Post | 28,156 | 71.19 | ||
| Mixed Member Proportional | 11,392 | 28.81 | ||
| Total valid votes | 39,548 | 100.00 | ||