June 1, 1931: "Telephone crews of the forest service are building a telephone line to the lookout tower on St. Mary's peak. The new lookout tower on the mountain peak west of Stevensville will be one of the best and highest lookout towers in the district when completed and it is said that the telephone system to it will be completed in a short time. For two weeks men have been digging holes and setting poles for the forestry line. It will connect with the main telephone line at the Stevensville bridge and will follow roads and lanes southwest to the foothills and then up the mountain side." (Independent - Helena)
July 8, 1934: "A Forest Service lookout station is to be built on the summit of St. Mary's peak, west of Stevensville. Materials are now being transported up the mountain to build the station, which, it is said, will command a far-reaching view. O.E. York, local ranger, is in charge of the work." (The Missoulian)
1951: The 50-foot timber tower destroyed during a wind storm.
August 20, 1952: "The lookout tower atop St. Mary's peak will be reconstructed to serve as a relay station for forest service frequency modulation radio communication, according to forest service officials in the Stevensville district. Originally the tower was to be abandoned since the cab was blown off in 1951 and conditions on the peak are too severe for firewatchers to live in tents. The new tower will use a recently designed cab mounted on a 12-foot stone masonry room. Only cement and sand will have to be carried to the peak as the stone needed for the construction is already available. It is hoped to have the job completed in time for use during the 1953 fire season." (Ravalli Republic)
1952: An eight foot timber tower with an L-4 cab constructed by the Forest Service.
1953: During the summer months, the lookout, Les James enclosed the tower with native rock. The finished work provided secure storage, complete with a door and windows.
June 13, 1962: "Saint Mary: Maurice Edwards, Stevensville, who attends Montana State College, Bozeman, and is studying electrical engineering." (Ravalli Republic)
June 21, 1963: "St. Mary's: Sam Little, Stevensville, who attends Montana State College, Bozeman, and is studying electrical engineering. This is Little's third year on the District." (Ravalli Republic)
July 3, 1969: "Kenneth Gerner will be stationed on St. Mary's lookout. He is from Stevensville. He is a junior at the University of Montana and is studying philosophy." (Ravalli Republic)
June 22, 1971: "Fire control officer Bob Graham said the old system of fire lookouts has been trimmed down slightly this season because of better detection methods. The Bitter Root Forest has closed St. Mary lookout on the Stevensville district." (Ravalli Republic)
1972: The lookout removed from the fire plan due to poor visibility after storms.
1998: The lookout underwent a complete exterior restoration with the aid of a Passport in Time volunteer project.