Ottawa Carnegie Library is a two story Neo-Classical building constructed with Andrew Carnegie's $15,000 grant, matched by the City with a site and a commitment to devote 10% of the gift amount annually for maintenance. Its design by George P. Washburn & Son, Architects, is distinguished by colossal order Ionic columns, a limestone watertable base, a terne metal roof with decorative ridge crest and hip covers, and a rotunda or hemicycle on the East. It is a contributing building in the Historic Ottawa Central Business District, which was placed on the National Register of Historic Places in 2007.