Thomas Mower Martin was a prolific painter, his works hang in a great many public and private collections in Canada, the United States, Scotland and Britain, especially one in Windsor Castle. The Glenbow Museum in Calgary, Alberta has the largest collection in Canada. They also have much of his memorabilia of journals, correspondence and more. The collections list includes:

• National Gallery of Canada, Ottawa
  
• Victoria Art Gallery
  
• Royal BC Museum, Victoria - BC Archives, Victoria
  
• Vancouver Art Gallery
  
• City of Vancouver Museum
  
• Glenbow Museum in Calgary
  
• Mendel Gallery, Saskatoon
  
• Winnipeg Art Gallery
  
• Department of Public Works City of Toronto Archives
  
• Windsor Castle, England 'The Untouched Wilderness'  1882
  
• Government of Ontario Art Collection
  
• Montreal Musée of Art
  
• Royal Ontario Museum
  
• Edmonton Public Library
  
• Robert McLaughlin Galley, Oshawa  ON
  
• University of Calgary Library
  
• Marquess of Landsdowne, England  
  
• Leland Collections, New York  
  
• City of Toronto Art Collection, Culture

Thomas Mower Martin's memberships in art organizations included:

Ontario Society of Artists, founding member 1872

Royal Canadian Academy of Art - founding member 1880

Association of Canadian Etchers, 1884

Royal British Colonial Artists Society, London  UK

Royal Society of Artists, London  UK