The Midlothian constituency was created at the same time as the Scottish Parliament, in 1999, with the name and boundaries of the then existing Westminster constituency. In 2005, however, Scottish Westminster (House of Commons) constituencies were mostly replaced with new constituencies.[1]
Following their First Periodic review of constituencies to the Scottish Parliament, the Boundary Commission for Scotland recommended extending the current Midlothian constituency into a newly formed seat of Midlothian North and Musselburgh with the western boundary to the south of Auchendinny. The other constituency now covering the Midlothian council area is a modified Midlothian South, Tweedale, and Lauderdale constituency.