Grenville South was a federal electoral district represented in the House of Commons of Canada from 1867 to 1904. It was located in the province of Ontario. It was created by the British North America Act of 1867.
The electoral district was abolished in 1903 when it was merged into Grenville riding.
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| Municipality | Shanly | Patrick | Total vote | Eligible voters | |
|---|---|---|---|---|---|
| 389 | 306 | 695 | 818 | ||
| 338 | 283 | 621 | 720 | ||
| Prescott East Ward | 64 | 51 | 115 | 149 | |
| Prescott West Ward | 61 | 46 | 107 | 159 | |
| Prescott South Ward | 47 | 44 | 91 | 128 | |
| Total | 899 | 720 | 1,629 | 1,974 |
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On Mr. Benson's death, 8 June 1885:|}
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