The Progressive Era is a name for time period around 1900 to 1920, associated with the ideas of the Progressive movement or Progressivism of that time period. Characteristics include increased power for the central government and more governmental interventions, notably for antitrust purposes, but also other areas such as prohibition laws against alcohol and conservation laws.
Despite sometimes less politically correct aspects, leftists tend to view it favorably, apparently viewing it as a precursor to various later leftist governmental interventions.
Less politically correct aspects include support by progressives for eugenics and racial segregation. Leftist Wikipedia despite this dubiously cites a claim that progressives "were responsible for bringing scientific racism to an end", despite that, for example, Boasian anthropology seems to have little in common with the racial views and policies of the Progressive Era.