This paper presents the preliminary results of the District Heating Atlas, an online tool to collect and visualize key metrics of district heating systems in Germany. Since the scarce available public information on district heating systems is widely spread and not accessible via central data, the District Heating Atlas shall be the platform to enter and call up information centrally. With its online platform it provides a user interface where relevant information can be entered and system components of the currently recorded 82 district heating systems can be compared. So far, nearly 50% of the thermal energy fed into district heating is covered by the District Heating Atlas. The analysis shows that the data availability is more than 60% for five of the ten key metrics recorded. On the one hand, missing correlations between the key metrics show the diversity of the district heating systems and make it difficult to formulate general valid statements that could help to calculate missing data. On the other hand, this means that district heating systems are very diverse in their structure and thus offer versatile potential for sector coupling. In addition, district heating systems must be individually optimised in order to best utilize their potential for flexibility for the entire energy system. Finally, the first comparisons with information from the biggest district heating association in Germany show a high match with the currently collected data set. ©2021 The Author(s). Published by Elsevier Ltd.