It comes as the County Councils Network said councils across the country have found it hard to balance funding towards arts and cultures while demand spikes for social care and children’s services.
Department for Levelling Up, Housing and Communities figures show Cornwall Council set a budget of £15.3 million for cultural services for 2024-25 – down 48% from £29.2 million in 2010-11, around the start of austerity.
Local authority funding for cultural services covers areas such as libraries, open spaces, tourism, museums, and recreation and sports.
Across England, this budgeted spending dropped by 25%, from £3.4 billion in 2010-11 to £2.5 billion this year.
Sam Corcoran, vice chair of the County Councils Network, said: "Councils are the biggest funders of arts and culture in England, and councils in county areas recognise the value of investing in libraries, arts and heritage attractions for both our communities and our economies.
"However, with central government funding reductions over the last 14 years, councils have found it increasingly hard to balance spend on cultural services with spend on adult social care, children’s services, and special educational needs provision."
Mr Corcoran said "scant resource" has consequently been ringfenced for services that have seen significant spike in demand and cost.
He added: "We understand the public finances are tight, but the case for an uplift in funding for councils is clear.
"Extra resource will mean less money would have to be re-prioritised from cultural services to care services, meaning local authorities can better protect libraries, museums and heritage – and free up investment into them."
Nationally, the biggest drop in budgeted spending was for recreation and sports, falling 50% from £862 million in 2010-11 to £434 million this year.
In Cornwall, spending on library services saw a particularly large fall – down 61%.