The Dominion Observatory is part of the Parliamentary Precinct. Buildings on or near the Precinct cannot be any taller than the Peace Tower.

 "The popularity of the Observatory occurred when it opened in 1905, due to the support of Prime Minister Sir Wilfrid Laurier. Laurier's advocation reinforced the idea that this Observatory was to be considered an arm of the parliamentary precinct...At the time it was recognized as a national achievement, where the nation's time would be kept, and (it) would be a symbol of Canada's progress in astronomical science." ("Journal of the Study of Architecture in Canada." "Astronomer Mary Grey and the Architecture of Canada's Dominion Observatory." Royal Astronomical Society of Canada-Sharon Odell. page 10/67.)

"The National Heritage of the Dominion Observatory" can be viewed on YouTube.

The Parliamentary Precinct also includes:

• the Parliament Buildings and the Hill
• Library of Parliament
• Supreme Court of Canada
• Senate of Canada (former Union Station)
• Library and Archives Canada
• Federal buildings on Wellington Street across from the Hill
• the northern half of the Sparks Street Mall
• Lebreton Flats, the western annex. House of Commons Ottawa November 23, 1967. The Hon. George McIlraith (Minister of Public Works): "The Lebreton Flats were envisioned as a western extension to the Parliamentary Precinct. Buildings on or near the Parliamentary Precinct cannot be any  taller than the Peace Tower."