The Electronic Lab Notebook (ELN) Comparison Matrix was created by the Longwood Medical Area Research Data Management Working Group (LMA RDMWG) in 2018 to aid Harvard researchers in the Longwood Medical Area in the process of identifying practical ELN tools to meet their specific research needs. To create a useful resource, a survey was sent to 26 ELN vendors and a matrix was created based on the responses. Since then, additional platforms were added, totaling 33 options. The tools listed in the ELN Matrix were selected strictly on their relevance to the LMA biomedical research community concerning their intended function to replace and enhance conventional (hard copy) laboratory notebooks. Inclusion of a tool in the ELN Matrix does not imply an endorsement by Harvard, and exclusion of a tool is based solely on relevance; no evaluations of tool quality were made or acted upon in developing the ELN Matrix. While targeted for Harvard researchers, this Electronic Lab Notebook Comparison Matrix has been recognized around the world on Twitter, Wikipedia, and recently in Nature, making it a go-to educational tool and decision map for librarians and researchers alike. In 2021, the LMA RDMWG made the decision to archive this project. This resource is no longer maintained by the LMA RDMWG and snapshots of the matrix were last captured on April 19, 2021, and the website pages were captured on May 5, 2021. Viewers can still explore the archived information, but it is suggested you visit the ELN product websites for the most up-to-date specifications.