We investigate molecular cloud formation in a magnetically dominated regime. Two atomic gas clouds with cold neutral medium (CNM) conditions are driven to collide at an interface of oppositely directed magnetic fields. The collision triggers magnetic reconnection, forming a ~20 pc filamentary cloud with rich fiber-like substructure. By 5 Myr, the filament develops a fully molecular spine. Radiative transfer modeling of far-infrared dust emission reveals dense cores distributed along the filament, some of which host one to a few sinks spread over a ~5 pc region near the filament center. High-resolution views show that sink-hosting cores are connected by dust fibers and associated with high-velocity CO emission, consistent with active accretion through streamers because surface fields act against inflowing gas. Supersonic turbulence in the filament is magnetically driven, arising from trans-Alfvénic magnetic transport. These results demonstrate that filamentary molecular clouds with observed physical properties can form in a magnetically dominated environment without the need for gravity (although gravity will later dominate), and are naturally wrapped by a helical/toroidal magnetic field that should produce reversed magnetic fields on opposite sides of the filament from most viewing angles.
