Canada's first Railway Tunnel is located in Brockville, ON and can be visited any day during the Spring, Summer and Fall.
The area inside the south portal can be visited when the doors are open. The entrance is located just south of the Water Street "hump". The tunnel travels completely under the Brockville City Hall as seen in the background of this photo. Trains used to pass underground for 1/3 of a mile for about 125 years from 1860 - 1975. They were going and coming from the Ottawa Valley, north of Brockville.