- Horsham is a market town and civil parish in West Sussex, England. It is located about 31 miles (50 km) southwest of London and 18.5 miles (30 km) northwest of Brighton. Horsham is known for its historic architecture, green spaces, and vibrant town center. It has a population of around 59,000 people and is the administrative center of the Horsham District. The town offers a range of amenities, including shopping centers, restaurants, parks, and leisure facilities. Horsham also has excellent transport links, with direct train services to London and other major cities.