The Sisters of Notre Dame Namur, who live at Lancaster House convent close to Parbold Village near Wigan, want to sell the property to a developer, after securing outline consent for a 70-unit care village at the site.
Lancaster House was built in 1845 and has been home to the Sisters of Notre Dame Namur since 1947. The order substantially extended the property in the mid-1980s to provide a nursing wing.
The order has three convents in total, but dwindling numbers mean it is looking to consolidate its assets and sell Lancaster House.
Property consultancy CBRE has been appointed to market the 6.5-acre development opportunity after planning consent was secured more than two years ago.
Under the outline plans, the main Lancaster House building would be converted into six apartments while the neighbouring coach house would contain nine apartments.
The 1980s additions to the property would be demolished and a new apartment block, comprising 56 one- and two-bedroom flats, would be built in their place. The outline planning consent provides for up to 70 units.
The development will also contain several communal facilities including a dining room and bistro, lounge, hairdressing salon, treatment room, rehabilitation gym and overnight guest accommodation.
Shaun Skidmore, senior director of operational real estate at CBRE Manchester, said: “The UK senior living market is undergoing rapid growth underpinned by an ageing population and demand for quality, specialist housing.
“This property and the site represents an opportunity to undertake a substantial redevelopment to provide a retirement village or an assisted living scheme.”