This work investigates the fixity of a set of archived webpages, or mementos. We conducted a study on 16,627 mementos from 17 public web archives. We replayed and downloaded the mementos 39 times using a headless browser over a period of 442 days and generated a hash for each memento after each download, resulting in 39 hashes per memento. The hashes were generated by creating Merkle trees to represent hashes at each level of the memento. A hash was generated for each resource used to construct the full webpage and then the hashes were combined to generate an overall hash for the composite memento. There are 39 data files, one for each download. The mementos downloaded come from the dataset at https://github.com/oduwsdl/mementos-fixity/