We compute the angular power spectrum Cl from 1.5 milliongalaxies in early Sloan Digital Sky Survey (SDSS) data on large angularscales, l<~600. The data set covers about 160 deg2, with acharacteristic depth on the order of 1 h-1 Gpc in thefaintest (21*<22) of our four magnitude bins.Cosmological interpretations of these results are presented in acompanion paper by Dodelson and coworkers. The data in all fourmagnitude bins are consistent with a simple flat ``concordance'' modelwith nonlinear evolution and linear bias factors on the order of unity.Nonlinear evolution is particularly evident for the brightest galaxies.A series of tests suggests that systematic errors related to seeing,reddening, etc. are negligible, which bodes well for the 60-fold largersample that the SDSS is currently collecting. Uncorrelated error barsand well-behaved window functions make our measurements a convenientstarting point for cosmological model fitting.