Midlothian is a county in Scotland, bounded on the east by East Lothian and Berwickshire, on the south by Roxburghshire, Selkirkshire and Peeblesshire, on the west by Lanarkshire and West Lothian, and on the north by the Firth of Forth. It covers an area of 366 square miles.
The surface is largely hilly, with the Pentland hills rising in the southwest to heights of 1900 feet, and in the southeast is an extension of the Lammermuir Hills. The chief rivers are the Esk, the Almond, the the Water of Leith, emptying into the Forth. The capital is Edinburgh, which is the chief city. Its port is Leith.