The SPURS (Salinity Processes in the Upper Ocean Regional Study) project is an oceanographic process study and associated field program that aim to elucidate key mechanisms responsible for near-surface salinity variations in the oceans. The project involves two field campaigns and a series of cruises in regions of the Atlantic and Pacific Oceans exhibiting salinity extremes. SPURS employs a suite of state-of-the-art in-situ sampling technologies that, combined with remotely sensed salinity fields from the Aquarius/SAC-D and SMOS satellites, provide a detailed characterization of salinity structure over a continuum of spatio-temporal scales. The SPURS-1 campaign involved a series of 5 cruises during 2012 - 2013 seeking to characterize the salinity structure and balance in a high salinity, high evaporation, and low rainfall region of the subtropical North Atlantic. It aims to resolve processes responsible for maintaining the subtropical surface salinity maximum in this region and within a 900 x 800-mile square study area centered at 25N, 38W. An Underway-CTD (UCTD) was deployed on 2 of the SPURS-1 cruises. An UCTD is a towed CTD instrument providing conductivity, salinity and temperature depth profile observations while underway at up to 20kts. 771 UCTD casts occurred during the Knorr and Endeavor-I cruises (6 Sept-9 Oct 2012 and 15 Mar-15 Apr 2013 respectively) utilizing an Oceanscience instrument. UCTD data files (1 per cruise) each contain the observational data for multiple deployments, binned in 1m depth intervals.