This thesis explores the social and operational expansion of the Nassau County Police Department on Long Island, New York from the years 1954 to 1971, illustrating the different articulated goals of the department during transitions such as police professionalization, the War on Crime, desegregation, and the Civil Rights Movement. It shows how the Department accumulated social and economic capital in Nassau County, especially during the 1960s, and earned its reputation as an essential institution during and after the Civil Rights Movement. This thesis also provides some social history of Black suburbanization and the how Black Nassau County residents understood and expressed their desires for political, social, and economic enfranchisement within the boundaries of suburban space during the 1950s, 60s, and 70s.