St. Thomas is a city in Southern (Southwestern), Ontario, Canada. It is the seat for Elgin County and gained its city charter on March 4, 1881.

The city, located at the intersection of two historical roads, was first settled in 1810. It was named the seat of the new Elgin County in 1844 and was incorporated  as a village  in 1852, as a town  in 1861. In 1871, St. Thomas and the nearby village of Millersburg (a village east of the town) amalgamated. In 1881 St. Thomas finally grew to become a city.

Ten years after the incorporation as a town, the developing village of Millersburg, which included these lands east of the London and Port Stanley Railway, amalgamated with St. Thomas.

In the late 19th century and early 20th century several railways were constructed through the city, and St. Thomas became an important railway junction. A total of 26 railways have passed through the city since the first railway was completed in 1856. In the 1950s and 1960s, with the decline of the railway as a mode of transportation, other industry began to locate in the city, principally primary and secondary automotive manufacturing.

Jumbo (the elephant) died here on September 15, 1885, when a locomotive crashed into him. There is a life-sized commemorative statue that was erected in 1985, on the centennial of Jumbo’s demise.

The city was named after Thomas Talbot who helped promote the development of this region during the early 19th century . The founder of the settlement that became St. Thomas was Capt. Daniel Rapelje, descendant of a Walloon family settled in New Amsterdam, now New York City, at its inception in the seventeenth century. In 1820, Rapelje, the town’s first settler, divided his land into town lots suitable for a village. Owner of the New England Mill, Rapelje subsequently donated two acres of land for the building of Old St. Thomas Church.

In 1824, Charles Duncombe and John Rolph established the first medical school in Upper Canada, in St. Thomas, under the patronage of Colonel Thomas Talbot.

Between 1881 and 1988 the city had a private woman’s school operating called Alma College (St. Thomas) which was destroyed by fire in 2008.

St. Thomas has a rich history of late 19th- early 20th centurary architecture. Notably these include the Elgin County Court House, Wellington Street public school, and its City hall, all designated heritage properties and all designed by former resident Neil R. Darrach.