In connection with studies of the practicability of conversion of saline water to fresh water, the U. S. Geological Survey assembled data on the occurrence, distribution, quantity, and chemical quality of saline waters as of 1955 for a report entitled, "Preliminary survey of the saline water resources of the United States" to be released when completed as a U. S. Geological Survey Water Supply Paper 1374. This report comprises data for New York State. Saline water is defined herein as any mixture of fresh and salt water having more than 1,000 parts per million (ppm) of dissolved solids. In the Nation as a whole there are, of course, all gradations of salinity from 1,000 ppm up to the 30,000 to 35,000 ppm characteristic of sea water, and the even higher salinities of certain natural brines. Sea water, and other water of comparable salinity, will be referred to here as "sea water" or "high-chloride water". This report contains two parts: one for Long Island, Staten Island, and Manhattan, N. Y., and the other for Upstate New York. Figure 1 shows the locations of the places named and important occurrences of saline water in and near Long Island. Tables 1 and 2 list, respectively, well data and chemical analyses for selected wells in Long Island, Staten Island, and Manhattan, N. Y.; tables 3 and 4 list, respectively, well data and chemical analyses for selected wells in Upstate New York. For many samples, only the chloride concentration and not the total dissolved solids has been determined. However, it is safe to assume that the total dissolved solids in natural water are substantially in excess of 1,000 ppm where the chloride is at or nearly at this concentration.