| Battalion and Staff H.Q. | Whitby | ||
| No. 1 | Company | Whitby | |
| 2 | " | Brooklin | |
| 3 | " | Oshawa | |
| 4 | " | Greenwood | |
| 5 | " | Port Perry | |
| 6 | " | Uxbridge | |
| 7 | " | Beaverton | |
| 8 | " | Pickering | |
| 9 | " | Columbus | |
| 10 | " | Cannington | |
Sometime afterwards the Battalion was reduced to seven companies, those at Greenwood, Port Perry and Columbus being eliminated.
In 1905 one more Company was added with Headquarters at Brechin and the distribution at the present time is as follows:—
| Regimental H.Q. | Whitby | ||
| A. | Company | Oshawa | |
| B. | " | Whitby | |
| C. | " | Oshawa | |
| D. | " | Beaverton | |
| E. | " | Uxbridge | |
| F. | " | Port Perry | |
| G. | " | Cannington | |
| H. | " | Oshawa. | |
During the Fenian Raids of 1866 and 1868, Ontario County contributed its quota and a number of Ontario County men saw service in the North-West Rebellion of 1885, some of whom are still living in the County.
When war broke out in August, 1914, recruiting centres were established throughout Ontario County, and almost immediately the 34th Regiment was asked to supply a draft of 125 men for the First Contingent.
So great was the response to the call for this draft that finally 7 officers and 200 other ranks went to Valcartier to join the 2nd and 4th Battalions.
During the interval between the departure of the First Contingent and the enrolling of the Second, a great deal of preparatory work was done, but recruiting was not the only military activity of the times, as there was considerable anxiety felt throughout the County regarding the attitude of the alien population.