St. Alphonsus Hospital was a three-story, French Renaissance style building in Boise, Idaho, designed by architect J.K. Hollowell in 1893. Completed in 1894, the hospital was part of a small group of buildings constructed by the Roman Catholic Diocese of Boise that included St. Teresa's Academy (demolished). Located at Fifth Street between State and Washington streets, the hospital building was added to the National Register of Historic Places in 1977, soon after it became slated for demolition in 1976. It was delisted shortly thereafter.