Weston Hall was demolished in the 1930s and a purpose-built structure, adjoining the Mappin Art Gallery, and funded in part by donations from local businessman J. G. Graves, was completed in 1937.

In December 1940 the Mappin Art Gallery suffered a direct hit in the Sheffield Blitz, destroying a significant part of the building and damaging much of the rest.

During the 1950s and 1960s the museum remained open to the public, whilst the Mappin Art Gallery was left in a partially demolished state after the structure had been made safe.

The museum's archaeology exhibits include a replica of the Bronze Age rock art from Gardom's Edge and many items collected by Thomas Bateman, notably the Benty Grange helmet which closely matches the descriptions of warriors' helmets in Beowulf.

[5] Weston Park museum receives around 250,000 visitors a year and was nominated for the prestigious Gulbenkian Prize in 2007.