Sefton Park, 3.5km south-east of the centre of Liverpool, was an exceptionally ambitious and costly outcome of the nineteenth-century public park movement. Its perimeter was set aside for high-class housing, and within 15 years of opening in 1872 the park had become the focus of an affluent new suburb. This article describes the process by which the houses came to be built and their architectural character. Taking the buildings as a starting point, it draws on a range of quantitative and qualitative sources—leasing records, census returns, contemporary biography, personal diaries and satirical journalism—to give an account of the social character of the area. The park-side houses reflect the mercantile wealth of late nineteenth-century Liverpool, but the verdict of some contemporary critics—that Sefton Park was a ghetto of nouveaux riches—turns out, not surprisingly, to be an over-simplification.