The Blanco Cosmology Survey is a four-band (griz) optical-imaging survey of ~80 deg super(2) of the southern sky. The survey consists of two fields centered approximately at (R.A., decl.) = (23 super(h), -55degrees) and (5 super(h)30 super(m), -53degrees) with imaging sufficient for the detection of Llow *galaxies at redshift z < or =, slant 1. In this paper, we present our reduction of the survey data and describe a new technique for the separation of stars and galaxies. We search the calibrated source catalogs for galaxy clusters at z < or =, slant 0.75 by identifying spatial over-densities of red-sequence galaxies and report the coordinates, redshifts, and optical richnesses, lambda, for 764 galaxy clusters at z < or =, slant 0.75. This sample, >85% of which are new discoveries, has a median redshift of z = 0.52 and median richness lambda(0.4 Llow *) = 16.4. Accompanying this paper we also release full survey data products including reduced images and calibrated source catalogs. These products are available at http://data.rcc.uchicago.edu/dataset/blanco-cosmology-survey.