This community walkway started out as part of the historic Grand Trunk Railway. In 1858, the GTR reached the small village of St. Marys from Toronto and points further east. From here, the line went west to Sarnia and then, on the other side of the Canadian American border, from Port Huron to Chicago. The major challenge for both structural engineers and contractors was the erection of this bridge to cross the Thames River. The bridge required a row of massive stone pillars to support the girders and tracks. It immediately became a landmark in St. Marys.
In 1995, the Town of St. Marys was able to purchase the Sarnia Bridge from the Canadian National Railway, as well as the right of way within Town limits along the abandoned line. A citizens' committee was formed in June, 1996, to work towards transforming this old railway line into a trail for everyone to enjoy - residents and visitors alike. The Grand Trunk Trail was opened in 1998 with 3.2 kilometers of paved, accessible trail. Without a doubt, the highlight of this walkway is the Sarnia Bridge with panoramic views south over the town and north to the beautiful countryside.