This ward obtained its name from an ancient castle, which stood here on the banks of the river. It is divided into precincts, and is under the government of an alderman, sending inhabitants to the court of common council. It is bounded on the east by and wards; on the south by the river Thames, and on the west and north by the ward of Farringdon within. Before the great fire in , there were churches in this ward, viz. St. Andrew, by the wardrobe; St. Benet, ; St. Mary Magdalene, , and St. Gregory; the remain.

Before describing the churches that remain, it will be proper to notice the metropolitan church, the principal part of which is in this ward. Stow and all the authors that have written on the history and antiquities of London, have uniformly placed under the head of Farringdon within, but upon minutely examining the plans of each of the wards, and consulting the parish and ward officers, the author is induced to place the church in the ward of Castle Baynard. The exact line of demarcation between the wards in the cathedral church is not known, but it is probable that if a line was drawn from the chapter house, which is in Farringdon within, to the south-east corner of yard, it would be near the truth.