Preston St Mary is located to the north-east of Lavenham and is part of Babergh district council area and Suffolk County Council.
The Parish Council is responsible for representing the community, making policy decisions and ensuring lawful and effective use of public funds. It provides grants to local organisations. It is responsible for the dog waste bins in the village, and provides a community voice on planning applications and other matters relating to the village.
The Parish Council liaises with Babergh District Council, who are responsible for issues such as waste collection, and Suffolk County Council who are responsible for matters such as Highways and Social Care. It also will liaise with local landowners who are are responsible for maintaining footpaths across their land.