These maps are highly detailed. They are taken from the OS 1:2,500 (or 25 inch) maps and reduced to about 15 inches to the mile. Each covers an area of a mile and a half by a mile. They show streets with individual houses, tram tracks, railway tracks and even signals, factories, wharves and such details as fountains and water troughs. They will provide hours of fascination for historians and genealogists. The maps are neatly folded and each includes a specially written introduction to the area.

There are three versions of this map, showing how the area developed across the years. The maps each cover the same area, the area north of Finsbury Park station (which is just off the foot of the map).

The 1870 map shows an almost rural area, just before the park was created. Coverage runs from Topsfield Hall at Crouch End southward to Fonthill Road, eastward to Manor House. Features include Stroud Green, Hornseywood Tavern, Northumberland House, Mount Pleasant, Crouch Hill station (on Tottenham & Hampstead railway), Manor House pub, numerous named villas and large houses in the Crouch Hill area. The GNR line runs north-south through the centre of the map. The GNR High Barnet branch and Tottenham & Hampstead lines are also shown. On the reverse is a directory of Crouch Hill in 1890.

The 1894 and 1912 maps show the area progressively more built up, especially with the development of Harringay, the opening of more railway stations and the development of Finsbury Park.

The map links up with London Sheets 12 Hornsey to the north, 19 Highgate to the west, 21 Stamford Hill to the east, 29 Upper Holloway to the south.