We retrieved front locations for 171 Svalbard tidewater glaciers in the 1960s and 1970s, from Landsat images and – for the first time in this region – declassified intelligence satellite photographs. We compared our results to aerial photographs from the 1930s and calculated that these glaciers retreated by about 1 km between 1936 and 1978. We also discovered one undocumented glacier surge (a rapid front advance), precised the time frames of two others, and documented two other glacier advances.