This chapter examines the emergence of San Francisco’s cross-dressing law at the crossroads of three forces: defining cross-dressing and prostitution as indecency, framing indecency as a societal problem in need of intervention, and identifying local law as the solution. The classification of indecency as a legal problem would have been unforeseeable at the beginning of the 1850s, when multiple indecencies were widely tolerated and local government rarely intervened in city life. However, as the decade unfolded, San Francisco underwent a series of changes that redefined the boundaries of normative gender and reworked local government into a proactive regulatory force. This did not indicate a shift from a “wide-open” frontier town to a “locked-down” police state, but it did signal the debut of a proactive local government that assumed new responsibilities for the social and moral order of the city.