The Horsham Constituency consists of 14 Horsham District Council Wards of Billingshurst, Broadbridge Heath, Colgate and Rusper, Denne, Forest, Holbrook East, Holbrook West, Itchingfield, Slinfold and Warnham, Nuthurst, Roffey North, Roffey South, Rudgwick, Southwater and Shipley and Trafalgar.
It also takes in and three Mid Sussex District Council Wards of Ardingly and Balcombe, Copthorne and Worth, and Crawley Down and Turners Hill.
For West Sussex County Council it takes in the following nine Divisions; Billingshurst, Broadbridge, Holbrook, Horsham East, Horsham Hurst, Horsham Riverside, Southwater and Nuthurst, St Leonards Forest and Worth Forest. It also shares Imberdown with Mid Sussex.
The constituency is located in a northern part of West Sussex, bordering the constituencies of Crawley, Arundel and South Downs to the south and west, Mid Sussex to the south and east, Mole Valley to the north and also sections of Guildford, Chichester and East Surrey. It is centred slightly east of the town of Horsham and is rectangular with the exception of a noticeable gap formed by the geographically smaller constituency of Crawley.
The parliamentary constituency of Horsham has returned a Conservative Member of Parliament ever since 1880. Horsham District Council and Mid Sussex District Council are both Conservative-controlled as is West Sussex County Council.