Officers were called by a member of the public shortly before 8.30pm last night following a report of suspicious activity involving a lorry on the A350 near Chippenham.
Officers attended the scene and located 15 people in the rear of the vehicle.
At this early stage of the investigation, officers believe they are all over the age of 16.
Colleagues from the ambulance and the fire service attended the scene and carried out initial medical checks - fourteen of these people are currently being conveyed to custody, while one person has been taken to hospital for further checks – they are not believed to be in a serious condition.
A road closure has been put in place on the A350 at the Kington Langley crossroads while the lorry is recovered.
In addition, one man, aged in his 50’s, has been arrested on suspicion of assisting with illegal entry and taken to Swindon custody for further questioning.