Reliable procedures that accurately map the surface insolation over large domains at high spatial and temporal resolution are of great benefit for making the predictions of potential and actual evapotranspiration required by a variety of hydrological and agricultural applications. Here, hourly and daily-integrated GOES insolation estimates produced at the University of Wisconsin-Madison are extensively compared to pyranometer insolation data from 11 sites in the United States Climate Reference Network (USCRN) over a continuous 15-month period. Such a comprehensive survey is necessary in order to examine the accuracy of the satellite insolation estimates over a diverse range of seasons and land-surface types. Overall, the results are very encouraging with average root mean square errors (RMSE) for clear and cloudy-sky conditions combined of 20% and 10%, respectively, for the hourly and daily-integrated GOES insolation estimates.