A watershed model of the Sacramento River Basin of northern California was developed to simulate the streamflow and suspended sediment transport to the San Francisco Bay Delta for fifty years (1958-2008) using the Hydrological Simulation Program -- FORTRAN (HSPF). To compensate for the large model domain and sparse data, rigorous meteorological development and characterization of hydraulic geometry were employed to spatially distribute climate and hydrologic processes in unmeasured locations. Parameterization techniques sought to include known spatial information for tributaries such as soils information and slope, and then parameters were scaled up or down during calibration to retain the spatial characteristics of the land surface in un-gaged areas. The hydrologic and suspended sediment calibration focused more heavily on the Sacramento River rather than the tributaries. Calibration and validation of the Sacramento River ranged from "good" to "very good" performance based upon a "goodness-of-fit" statistical guideline. Model calibration to measured sediment loads were underestimated on average by 39% for the Sacramento River, and model calibration to suspended sediment concentrations were underestimated on average by 22% for the Sacramento River. A slight decreasing trend is evident in the modeled suspended sediment from 1958-2008, and is statistically significant (p