M&S is looking to close its store in Boston and 49 staff are facing redundancy.
The move comes as the retailer is shutting down unprofitable stores.
Paula Varley, M&S’ regional head, said “it has not been an easy decision to make”.
“Over the coming weeks we’ll be talking to each colleague individually as we go through the consultation process,” she added.
A final decision is expected later this year.
The nearest stores will be in the Springfields Outlet near Spalding, the Simply Food store in Spalding, and the Skegness Foodhall.