The Bishop of London is the ordinary of the Church of England Diocese of London in the Province of Canterbury.
The diocese covers 458 km² (177 sq. mi.) of 17 boroughs of Greater London north of the River Thames (historically the County of Middlesex ) and a small part of the county of Surrey. The see is in the City of London where the seat is located at the Cathedral Church of Saint Paul which was founded as a cathedral in 604 and was rebuilt from 1675 following the Great Fire of London (1666).
Third in seniority in the Church of England after the Archbishops of Canterbury and York, the bishop is one of five senior bishops, with the Archbishop of Canterbury, the Archbishop of York, the Bishop of Durham and the Bishop of Winchester, who sit as of right, each as one of the 26 Lords Spiritual in the House of Lords (as opposed to the remaining diocesan bishops of lesser rank, for whom elevation to one of the seats reserved is attained upon its vacancy and is determined by chronological seniority).
The bishop's residence is The Old Deanery, Dean's Court, London. Previously, for over a 1000 years, Fulham Palace was the residence although, from the 18th century, London House next to the Bishop's Chapel in Aldersgate Street was where he had his chambers.
The Bishop of London originally had responsibility for the church in the British colonies in North America, although after the American Revolution of 1776, all that remained under his jurisdiction were the British West India Islands.
More information, including a list of bishops, on the Wikipedia page