Baitun Nur (also spelled Baitunnur or Baitun Noor) (Arabic for "House of Light") is a mosque of the Ahmadiyya Muslim Community in the Castleridge community of Calgary, Alberta. It is known for being the largest mosque in Canada. It is estimated that there are about 3,000 members of the Ahmadiyya Muslim Community in Calgary. The cornerstone of the mosque was laid in 2005. Construction was completed in 2008 for an estimated cost of C$ 15 million, with roughly C$ 8 million of that coming from local Calgarians.