A new, fully sampled, sensitive CO survey of 52.5 square degrees towar
ds the Monoceros OB 1 (Mon OB 1) region has been completed using the C
fA 1.2 m millimeter-wave radio telescope. This survey extends from b =
-1.5 degrees to b = +3.5 degrees and from l = 196.0 degrees to l = 20
6.5 degrees on a uniformly spaced grid of 3.75' in l and b, and has su
bstantially better sensitivity than previous surveys of the region. CO
is detected in 80% of the area, 60% of which is weak with integrated
intensities less than 5 K km s(-1). The large-scale kinematics are dom
inated by the Perseus and Local spiral arms. Within the Local arm the
molecular gas appears to have been strongly influenced by supernova re
mnants and expanding H II regions with the strongest emission at veloc
ities ranging from -17 to +10 km s(-1), and a total mass of 1.3 x 10(5
) M.. Weak CO emission from Perseus arm clouds shows that they have a
mean kinematic distance of 3.5 kpc and are comparable in size and mass
to local molecular clouds. The coincident positions of colour selecte
d IRAS point sources indicates that these distant clouds are undergoin
g massive star formation.