We use Spitzer-IRAC data to identify near-infrared counterparts to
submillimeter galaxies detected with Herschel-SPIRE at 250 μm in the
Herschel Astrophysical Terahertz Large Area Survey. Using a likelihood
ratio analysis we identify 146 reliable IRAC counterparts to 123 SPIRE
sources out of the 159 in the survey area. We find that, compared to the
field population, the SPIRE counterparts occupy a distinct region of the
3.6 and 4.5 μm color-magnitude space, and we use this property to
identify 23 further counterparts to 13 SPIRE sources. The IRAC
identification rate of 86% is significantly higher than those that have
been demonstrated with wide-field ground-based optical and near-IR
imaging of Herschel fields. We estimate a false identification rate of
3.6%, corresponding to 4-5 sources. Among the 73 counterparts that are
undetected in Sloan Digital Sky Survey, 57 have both 3.6 and 4.5 μm
coverage. Of these, 43 have [3.6] - [4.5] > 0, indicating that they
are likely to be at z >~ 1.4. Thus, ~40% of identified SPIRE galaxies
are likely to be high-redshift (z >~ 1.4) sources. We discuss the
statistical properties of the IRAC-identified SPIRE galaxy sample
including far-IR luminosities, dust temperatures, star formation rates,
and stellar masses. The majority of our detected galaxies have
1010-1011 L ⊙ total IR luminosities
and are not intense starbursting galaxies as those found at z ~ 2, but
they have a factor of 2-3 above average specific star formation rates
compared to near-IR selected galaxy samples.