Arlesey is a small industrial town and civil parish in the district of Central Bedfordshire in Bedfordshire. It is located on the border with Hertfordshire, about three miles north-west of Letchworth Garden City, four miles north of Hitchin and six miles south of Biggleswade. Arlesey railway station provides train services to London, Peterborough, York and Edinburgh. Arlesey Town Football Club and Arlesey Athletic Football Club have their grounds to the south of the town.
The Domesday book mentions Arlesey as a market town. Residents have claimed it to be the longest town in Britain.
St Peters Church, situated in the Church End part of the town, was built in the 11th century by the monks of Waltham Abbey. Arlesey was the site of Etonbury Castle, of which little trace remains.