This database on marginal, underutilized and contaminated lands (MUC) was compiled based on multiple sources. The sources include: results from related EU and international projects that have already produced valuable tools, maps, and information, which addresses sustainable bioenergy production on MUC lands; data provided by governments as well as public and private stakeholders and; results of remote sensing-based classification of underutilised lands in terms of time series analysis to complete the gaps. The mapping of underutilized lands was conducted on two levels: TIER-1: Pan-European mapping of underutilized lands. More information on this approach can be found here: https://doi.org/10.3390/land10020102 TIER-2: Mapping of underutilized lands in case study areas in six different countries (Germany, Hungary, Italy, Romania, Spain and Ukraine). More detailed delineation of underutilized land patches based on input data with higher spatial and temporal resolution that used within the TIER-1 approach and additional local data. Data sets for the six case study countries published on Zenodo combine TIER-1 and TIER-2 mapping results, e.g TIER-1 results of case study areas are replaced by TIER-2 results. More information on the generation of the contaminated lands data set can be found here https://doi.org/10.3390/en14061566 Terms of use: These data are provided "as is". The authors make no warranty, representation, or guaranty of any type as to the completeness, accuracy, content or fitness for any particular purpose or use of any open data set made available here, nor shall any warranties be implied with respect to the data provided.