We characterize the SWIRE galaxy populations in the SWIRE validation field within the Lockman Hole , based on the 3.6-24 \mu Spitzer data and deep U , g ^ { \prime } , r ^ { \prime } , i ^ { \prime } optical imaging within an area \sim 1/3 sq .
deg for \sim 16,000 Spitzer-SWIRE sources .
The entire SWIRE survey will discover over 2.3 million galaxies at 3.6 \mu m and almost 350,000 at 24 \mu m ; \sim 70,000 of these will be 5-band 3.6-24 \mu detections .
The colors cover a broad range , generally well represented by redshifted spectral energy distributions of known galaxy populations , however significant samples of unusually blue objects in the [ 3.6-4.5 ] \mu m color are found , as well as many objects very red in the 3.6-24 \mu m mid-IR .
Nine of these are investigated and are interpreted as star-forming systems , starbursts and AGN from z=0.37 to 2.8 , with luminosities from L _ { IR } =10 ^ { 10.3 } to 10 ^ { 13.7 } L _ { \odot } .