This report is part of a comprehensive long-term project undertaken by HRNK to use satellite imagery and former detainee interviews to shed light on human suffering in the Democratic People’s Republic of Korea (DPRK, more commonly known as North Korea) by monitoring activity at political prison facilities throughout the nation. This report provides an abbreviated update to our previous reports on a long-term political prison commonly identified by former prisoners and researchers as Kwan-li-so No. 25 by providing details of significant activity observed during 2016–2021.