- Orange Cove (253 Companies)
- Orangevale (1,867 Companies)
- Orcutt (50 Companies)
- Oregon House (28 Companies)
- Orick (9 Companies)
- Orinda (1,157 Companies)
- Orland (964 Companies)
- Orleans (10 Companies)
- Oro Grande (32 Companies)
- Orosi (245 Companies)
- Oroville (4,872 Companies)
- Oxnard (12,373 Companies)
- Pacheco (70 Companies)
- Pacific Grove (1,481 Companies)
- Pacific Palisades (1,617 Companies)
- Pacific Plsds (64 Companies)
- Pacifica (1,587 Companies)
- Pacoima (3,564 Companies)
- Paicines (31 Companies)
- Pala (44 Companies)
- Palermo (61 Companies)
- Palm Desert (7,828 Companies)
- Palm Springs (5,587 Companies)
- Palmdale (7,598 Companies)
- Palo Alto (7,654 Companies)
- Palo Cedro (364 Companies)
- Palo Verde (10 Companies)
- Palomar Mountain (13 Companies)
- Palomar Park (48 Companies)
- Palos Verdes Estates (41 Companies)
- Palos Verdes Peninsula (1,690 Companies)
- Panorama City (2,768 Companies)
- Paradise (2,202 Companies)
- Paramount (3,826 Companies)
