We have identified and classified Zeeman pairs in the survey by Argon, Reid,
& Menten of massive star-forming regions with 18 cm (2 Pi 3/2, J = 3/2) OH
maser emission. We have found a total of more than 100 Zeeman pairs in more
than 50 massive star-forming regions. The magnetic field deduced from the
Zeeman splitting has allowed us to assign an overall line-of-sight magnetic
field direction to many of the massive star-forming regions. Combining these
data with other data sets obtained from OH Zeeman splitting, we have looked for
correlations of magnetic field directions between star-forming regions
scattered throughout the Galaxy. Our data do not support a uniform,
Galactic-scale field direction, nor do we find any strong evidence of magnetic
field correlations within spiral arms. However, our data suggest that in the
Solar neighborhood the magnetic field outside the Solar circle is oriented
clockwise as viewed from the North Galactic Pole, while inside the Solar circle
it is oriented counterclockwise. This pattern, including the magnetic field
reversal near the Sun, is in agreement with results obtained from pulsar
rotation measures.Comment: 37 pages AASTeX, including 6 figures, to appear in Ap