The Blanco Cosmology Survey is 4-band ( griz ) optical-imaging survey that covers \sim 80 deg ^ { 2 } of the southern sky .
The survey consists of two fields roughly centered at ( RA , DEC ) = ( 23h , -55d ) and ( 5h30m , -53d ) with imaging designed to reach depths sufficient for the detection of L _ { \star } galaxies out to a redshift of one .
In this paper we describe the reduction of the survey data , the creation of calibrated source catalogs and a new method for the separation of stars and galaxies .
We search these catalogs for galaxy clusters at z \leq 0.75 by identifying spatial over-densities of red-sequence galaxies .
We report the coordinates , redshift , and optical richness , \lambda , for 764 detected galaxy clusters at z \leq 0.75 .
This sample , > 85 % of which are new discoveries , has a median redshift of 0.52 and median richness \lambda ( 0.4 L _ { \star } ) of 16.4 .
Accompanying this paper we also release data products including the reduced images and calibrated source catalogs .
These products are available at http : //data.rcc.uchicago.edu/dataset/blanco-cosmology-survey .