The Horsham Constituency is home to an electorate of about 77,000 voters. The constituency lies wholly within West Sussex and, at a local-government level, is the responsibility of West Sussex County Council at County level. In terms of District Councils, the constituency is administered by Horsham District Council.
Under the structure of West Sussex County Council, the constituency takes in the following eight Divisions wholly within its boundaries;
- Billingshurst
- Broadbridge
- Holbrook
- Horsham East
- Horsham Hurst
- Horsham Riverside
- Southwater and Nuthurst
- St Leonards Forest
In addition the Division of Henfield falls partly into the parliamentary constituency Arundel and South Downs.
Under the structure of Horsham District Council, the constituency takes in the following 16 Wards wholly within its boundaries;
- Billingshurst
- Broadbridge Heath
- Colgate and Rusper
- Cowfold, Shermanybury and West Grinstead
- Denne
- Forest
- Holbrook East
- Holbrook West
- Itchingfield, Slinfold and Warnham
- Nuthurst
- Roffey North
- Roffey South
- Rudgwick
- Southwater North
- Southwater South and Shipley
- Trafalgar
The constituency is located in a northern part of West Sussex.