Welcome to the Johnston Rhode Island Police Department's website. The Johnston Police Department has provided community services for the people of Johnston RI for more than 100 years, and through advancements in technology, training, and professional development, the Johnston Police Department has evolved into one of the finest law enforcement organizations that this state has to offer. Serving approximately 30,000 residents, in nearly 12,000 households, on over 27 square miles, the Town of Johnston has quickly grown into one of the busiest, most geographically diverse and industrialized communities in the State of Rhode Island.