Unless otherwise stated on the examination announcement or job specification, applicants do not have to be a citizen. Applicants must be legally able to work in the United States. Applicants do have to be a citizen to be eligible to become a police officer.
For most positions, applicants do have to be a resident to participate in the examination. There are some positions that do not require residency. The examination announcement will indicate such a requirement under the “Residence” section.