St Marys is encounted when traveling the Launceston to St Helens/Bicheno (or vice versa) Fingal Valley route. St Marys is a very old town that supported railway growth in the very early days. St Marys is a tiny town nestled under the impressive St Patrick's Head, the most prominent rocky outcrop in the district.
The first European contact with the district occurred when Captain Tobias Furneaux sighted and named the 694 metre St Patrick's Head in 1773. The early settlement of Van Diemen's Land, which mostly occurred between Hobart and George Town, took little interest in the St Marys area.
It wasn't until the 1840s that a probation station, housing 300 convicts, was built at Grassy Bottom between the town and St Mary's Pass. They were assigned to build the road across the mountains to the east coast. This was done between 1843 and 1846. The arrival of the railway in 1866 led to town's increasing importance as a service centre. The railway line which was once so vital to the health of the town is now closed although the railway station (as a museum) still stands.