CA45, CA-45, or CA 45 may refer to:
California's 45th congressional district, a congressional district in the U.S. state of California California State Route 45, a state highway in California , a United States Navy cruiser Calcium-45 (Ca-45 or 45Ca), an isotope of calcium Caproni Ca.45, an Italian aircraft Mikawa-Ōtsuka Station, a railway station in Gamagōri, Japan (station code: CA45)