Upper Holloway is an area in the London Borough of Islington, London, centred on the upper part of Holloway Road and Junction Road, forming part of North London. The part of the Great North Road through north of the parish of Islington was known as the Holloway by 1307, a name later applied to the communities that formed along it. Upper Holloway is th…Upper Holloway is an area in the London Borough of Islington, London, centred on the upper part of Holloway Road and Junction Road, forming part of North London. The part of the Great North Road through north of the parish of Islington was known as the Holloway by 1307, a name later applied to the communities that formed along it. Upper Holloway is the original designation of the N19 postal district and the term is still used by the Royal Mail.