Regulations are "designed to implement, interpret, or prescribe law or policy or to describe the procedure of practice requirements of an agency" - E.O. 12866, section 3(d)
Many laws enacted by Congress require agencies to issue regulations. Executive branch agencies are granted the power to implement regulations relating to matters within their jurisdiction.
Agencies translate laws into detailed and precise rules for implementing statutes assigned to them. Regulations have the force and effect of law.
The above applies to both federal and state agencies.
60 FR 41578 = volume 60 of the Federal Register, page 41578
42 CFR 102.34 = title 42 of the Code of Federal Regulations, section 102, subsection 34