[en] Preliminary results of ground water, stream sediment, and stream water reconnaissance in the National Topographic Map Series (NTMS) Williamsport 1⁰ x 2⁰ quadrangle are presented. Stream sediment and stream water samples were collected from small streams at 970 sites or at a nominal density of one site per 18 square kilometers in rural areas. Ground water samples were collected at 1276 sites or at a nominal density of one site per 15 square kilometers. Neutron activation analysis (NAA) results are given for uranium and 16 other elements in sediments, and for uranium and 8 other elements in ground water and surface water. Field measurments and observations are reported for each site. Analytical data and field measurements are presented in tables and maps. Statistical summaries of data and a brief description of results are given. A generalized geologic map and a summary of the geology of the area are included. Key data from ground water sites include (1) water chemistry measurements (pH, conductivity, and alkalinity), (2) well depth, (3) element analyses (U, Br, Cl, F, Mn, Na, and V), and (4) graphical presentation only of Al and Dy analyses. Supplementary data include site descriptors (well age, frequency of use of well, etc.) and tabulated analytical data for Al and Dy. Key data from stream sediment sites include (1) water quality measurements (pH, conductivity, and alkalinity), and (2) important elemental analyses (U, Th, Hf, Al, Ce, Fe, Mn, Sc, Na, Ti, and V). Supplementary data from stream sediment sites include sample site descriptors (stream characteristics, vegetation, etc.) and additional elemental analyses (Dy, Eu, La, Lu, Sm, and Yb). Key data from stream water sites include (1) water chemistry measurements (pH, conductivity, and alkalinity) and (2) elemental analyses