Thomas Marks (June 21, 1834 – July 9, 1900) was an Irish-born Canadian businessman who served as the first mayor of Port Arthur, Ontario (later part of Thunder Bay). He was born in Kilfinane, the son of Samuel Marks, and came with his family to Bytown in Upper Canada in the 1840s. In 1857, he opened a general store with his brother George at Bruce Mines. In 1868, they opened a branch at the Landing (later Prince Arthur's Landing and then Port Arthur) and, in 1871, at Sault Ste Marie. Marks became a resident of Prince Arthur's Landing and lobbied for the establishment of a railway station there on the proposed transcontinental railway; however, nearby Fort William was favoured by the government as the site of the station. He then led the push for the construction of the Prince Arthur's Land