The Public Libraries Act (1850) marked a turning point in British history, establishing public libraries as we recognise them today. Since its inception, public libraries have remained at the heart of communities, persevering through numerous challenges to meet the diverse needs of their users. To mark the 175th anniversary of the Act, this systematic literature review was commissioned with the aim to compile recent research which demonstrates the value and impact of public libraries in the United Kingdom, whilst also identifying characteristics and deficiencies within the current research landscape. A core search string was developed, translated and applied to six databases, in addition to four sources of grey literature to capture non-academic publications. Analysis of the resulting literature highlighted the prevalence of qualitative, grey literature which centred mostly on the experiences of public libraries in densely-populated areas of England. Overall, six key themes were identified which illustrate the value and impact of public libraries in the UK. Four of these themes aligned with the Universal Library Offers designed by Libraries Connected (Culture and Creativity, Health and Wellbeing, Information and Digital, Books and Reading), whilst two separate themes emerged concerning Economic Value and Impact as well as Library Space and Place. The review findings show that public libraries play a vital role within their communities by providing free access to collections, technology, training and trustworthy information which fosters lifelong learning, entrepreneurship, cultural engagement and active citizenship. Alongside meeting the emotional and social needs of their users, public libraries offer multifunctional hubs which contribute to social justice and economic development, emphasising their continued relevance and resilience. This review manages to capture recent evidence which accurately represents the enduring value and impact of public libraries in the UK, and maps the current research landscape in order to inform future study.