This report describes the geology, ground-water conditions, streamflow characteristics, and quality of water in the West Milton area, Saratoga County, N.Y. The West Milton area is in the east-central part of New York in the hilly region that forms a transition zone between the Adirondack Mountains and the Hudson-Mohawk valley lowland. Bedrock underlying the area consists of crystalline rocks of Precambrian age and sandstone, dolomite, limestone, and shale formations of Cambrian and Ordovician age. The formations have been moderately folded and have been displaced as much as several hundred feet' along at least three northeast-trending normal faults. The bedrock is overlain in nearly all parts of the area by a layer of unconsolidated deposits which ranges in thickness from a few feet to more than 200 feet. The unconsolidated deposits are of Pleistocene age and consist of unstratified materials (till) laid down by glacial ice at stratified sediments deposited by glacial meltwaters. The topography of the bedrock surface differs greatly from the topography of the land surface. Although not evident in the present topography, at least two channels, cut in bedrock by preglacial streams, pass through the area. Ground-water supplies adequate to satisfy domestic requirements can be obtained from wells in any part of the area. Large ground-water supplies may be taken from coarse-grained stratified deposits comprising two aquifers in the valley of Kayaderosseras Creek. The Atomic Energy Commission has pumped as much as 1 mgd from a horizontal well drawing from the uppermost aquifer which is composed of flood-plain deposits. Part of the water yielded by this well during extended periods of pumping is induced flow from the creek. Three nearby vertical wells drilled by the Commission comprise a separate well field capable of yielding at least 2 mgd and possibly as much as 3 mgd from the deeper stratified deposits underlying the valley. A pumping test showed that at near the center of this well field the coefficient of transmissibility is about 125,000 gpd per ft and the coefficient of storage is about 0.0003. The water obtained from the sand and gravel has a hardness of about 125 ppm and contains about 150 ppm of dissolved solids. Most of the Government reservation is drained by Glowegee Creek, one of the larger tributaries of Kayaderosseras Creek. The average streamflow of Kayaderosseras Creek at West Milton is 141 cfs or about 1.5 cfs per sq. mi. The monthly mean discharge has ranged from a low of 21.7 cfs in September 1958 to a high of 866 cfs in March 1936, and the annual mean discharge has ranged from 94.5 cfs in 1941 to 198 cfs in 1952. The mean annual flood is 1,740 cfs and the 50-year flood is 5,300 cfs. Streamflow data have been collected on Glowegee Creek since 1948 at a station 0.5 mile south of West Milton. The average streamflow of Glowegee Creek at this station is 41 cfs or about 1.5 cfs per sq mi. The mean annual flood is 740 cfs and the 50-year flood is 2,250 cfs. The quality of the water in both Kayaderosseras Creek and Glowegee Creek is satisfactory for public supply and most industrial purposes. The mineral content of both streams is low--the dissolved-solids content averaging about 93 ppm in Kayaderosseras Creek and about 131 ppm in Glowegee Creek. The average hardness of water in Kayaderosseras Creek and Glowegee Creek is 68 ppm and 102 ppm, respectively. During periods of low flow, suspended sediment discharge in both streams is less than 10 tons per day, but during periods of high flow, the sediment discharge has been as great as 163 tons per day in Glowegee Creek and 437 tons per day in Kayaderosseras Creek.