The building on Swan Road was first designed as the Promenade Rooms - a space where genteel spa-takers in early-19th-century Harrogate could walk and gather between treatments. It later became the Victoria Reading Rooms and a library from 1839. Architect Arthur Hiscoe rebuilt it between 1874 and 1876, adding the handsome Italian Renaissance stone frontage that still defines the building today: five bays with round-arched windows, a Corinthian portico, a tympanum carrying the borough arms, and two tall pavilions topped with French-style ashlar fishtail slate roofs. The interior, with coffered ceilings and pilasters, was elegant by the standards of a small spa town. At various later points the building served as a housing benefits office. It became the Mercer Gallery in 1991, opened by George Lascelles, 7th Earl of Harewood, with a collection that already numbered at least 1,000 works.

The collection has since grown to over 2,000 items, mostly 19th- to 21st-century. Most of the time, most of those works are in storage. The Mercer keeps a rolling series of themed exhibitions drawn from its own collection alongside loaned shows - a model that lets the gallery feel constantly fresh in a way that a permanent hang never can. The artist list reads like a survey of British painting: William Powell Frith, the Victorian narrative master born exactly 200 years before the gallery's 2019 retrospective in his honour. John Atkinson Grimshaw, whose moonlit Yorkshire scenes inspired Whistler. Walter Sickert. Henry Moore. Paul Nash. Edward Wadsworth. George Frederic Watts. Vlaho Bukovac. John Lavery. Augustus Wall Callcott. Local artists sit beside international names. Sculpture by William John Seward Webber appears alongside paintings by Florence Fitzgerald and works inherited from the Kent Collection of Antiquities, donated to Harrogate Council in 1968.

Recent exhibitions show the Mercer's curatorial instincts. In January 2018, Picturing Women opened to mark the centennial of women's enfranchisement in Britain, hanging works by female artists from the collection - Eileen Cooper's Touchstone, pieces by Sonia Lawson and Sarah Pickstone, Rose Garrard's Artist as a Model, photographs by Julia Margaret Cameron. In 2020 and 2021, when the pandemic made physical exhibitions impossible, the gallery ran online open calls - React2: Art Created Through Covid-19, then React2, Our Planet, Our Home about climate change. In 2022, Celebration: British Abstract Painting drew nearly 60 paintings by 12 artists, including Patrick Heron, Gillian Ayres, and John Hoyland. In 2023, Yorkshire-born Martin Creed filled the gallery with over a thousand balls of different sizes for Artist Rooms. Each exhibition reframes the collection without exhausting it.

Two recent acquisitions tell the Mercer's story in miniature. In 2022, the local historian Malcolm Neesam bequeathed his Walker Neesam Archive - a lifetime's research into Harrogate's past - to the gallery. The 2024 exhibition Harrogate's Historian: A First Look at the Walker Neesam Archive let visitors see the documents, photographs, and ephemera that one man's obsession had gathered. The same year, the gallery showed Eva Leigh Walker, drawings and silhouettes by an early-20th-century female artist whose work had been rediscovered. The Mercer has space for the local historian's lifelong devotion and the forgotten Edwardian woman in the same season. North Yorkshire Council, which owns the gallery, keeps admission free. The building has ramped access at a side door, a hearing induction loop, and accessible toilet facilities. The art is for everyone - including the 19th-century spa-takers who would have walked these rooms when they were still Promenade Rooms, and might recognise the building if not what now hangs on the walls.