Bishop Pinkham and Dean Paget suggested putting up a building on Church of England property and renting it to the school. This was done and in September 1905, the school was opened with Mrs. Gerrie-Smith as principal. For the next forty-four years the school building occupied most of the block at 8th Street and 12th Avenue. The School followed the English example of training young women in the fine arts and higher education. Dean Paget suggested the name of St. Hilda and presented the school with an engraving of the ancient college of St. Hilda's of Whitby, England.
The college opened with about twenty resident pupils. Some from Edmonton, Lethbridge, Medecine Hat and from various ranches in the province. They had children from 5 to 18 years of age. There were also about 20 day pupils.
Mrs Gerrie-Smith and her daughter stayed until 1908 at which time the attendance had increased to 80 pupils in all and the building had been enlarged. As a result of World War I the enrollment dropped to thirty-five students. St. Hilda's College was renamed St. Hilda's School for Girls and became non-denominational; thus it was the first independent school in Calgary. During the period of World War II the School's enrollment increased quite dramatically as students from war-torn England dominated the boarding facilities. At one point in the 1940's the enrollment stood at one hundred and thirty pupils with a staff of twelve teachers. Nevertheless, in March of 1949 the Board of Governors announced the closure of the School which was completed in June of that year.
After the closure of St. Hilda's School for Girls, ten years passed before renewed demand for private education caused several of St. Hilda's former board members and financial backers to set up Tweedsmuir, an independent day school for girls. On opening day in September of 1959 the School had an enrollment of twenty-seven girls in Grades seven to nine. The following year the enrollment doubled and under the direction of Mrs. Ingeburg Aitkin as Headmistress, the School started to meet the objectives of the Board.
In 1971, helped by a substantial donation from the St. Hilda's Trust Fund, Tweedsmuir was amalgamated with Strathcona School for Boys (founded 1929) and established in its present location on 160 acres in a spectacular country setting. Strathcona-Tweedsmuir School (STS) is now a well-established co-educational, university preparatory school, which offers a challenging academic program to 680 students.
In early February 2003, the school was in the news as students on the annual cross-country ski trip were caught in an avalanche, just outside of Revelstoke B.C. There were 7 seven student fatalities.