Arlesey is a small town and civil parish in Bedfordshire. It is near 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 services to London, Stevenage and Peterborough. The Domesday Book mentions Arlesey.

Arlesey Old Moat and Glebe Meadows, adjacent to Arlesey railway station, is a nature reserve managed by the Wildlife Trust for Bedfordshire, Cambridgeshire and Northamptonshire, together with Arlesey Conservation for Nature.

The Arlesey Bomb fishing weight was developed by angler Dick Walker to catch specimen perch from the local chalk pits.

Arlesey had a thriving brick making industry through to the mid twentieth century. As of 1900 there were five brickworks around the town. They were known for the Arlesey White bricks produced from Gault clay. Bricks have not been produced there since 1992. Some clay pits have been used for landfill and others are now lakes. On the south east side of the town there were two chalk pits operated by the Portland Cement Company. The Blue Lagoon is now used for sailing and the Green Lagoon for fishing.

St Peter's Church in Church End was built in the 12th century by the monks of Waltham Abbey. Arlesey was also the site of Etonbury Castle, of which little trace remains. There is also a Methodist church in Arlesey.

On 19 December 1943 a Handley Page Halifax belonging to 138 Squadron was in a collision with a chimney at Arlesey Brickworks. The aircraft BB364 (NF-R) had left its base at RAF Tempsford on a training mission. The crew of nine perished in the subsequent crash.

On 28 March 1944 a Lockheed Hudson belonging to 161 Squadron RAF crashed on the Arlesey to Stotfold road killing the crew. The aircraft FK767 had left its base at RAF Tempsford on a training flight.