This paper analyses structures of the inland terminal markets that constitutes one of the main parts of the intermodal freight transport supply chains markets, by developing two different heuristic approaches to define the market. The main questions that this paper will answer are: 1. how can the terminal market be defined, 2. how can limited data about terminals be used to analyse the market structure, and 3. what are the structures of different terminal submarkets in the European Union. Although a lot of work has been done on intermodal freight transport, little has been done on quantitative analysis of intermodal markets, especially intermodal terminal markets. This paper develops two different approaches comparatively to define inland terminal markets. The first approach segments the market using the distance of terminals from central points of demand, while the second approach uses the aggregate trade in each of the demand areas. The results of the two different approaches have been used to validate the approaches, and show that the both approaches could be used in situations we have limited data. By using concentration indexes to calculate the market structures of 18 main areas in the European Union, we find that the inland terminal markets in EU are oligopolistic markets, characterized mainly by high concentration. The north of EU shows less concentration than the central & southern regions. According to the second approach, the terminal markets have higher degree of concentration, in comparison to the first approach. In some market areas, barge terminals also play a role which results in lower concentration levels. The structure of terminal markets suggests that terminals have a favorable negotiation power in the intermodal freight transport supply chains, which could be used as an important parameter to construct coordinated intermodal freight transport supply chains, because coordination in supply chains can be achieved by creating incentives for the parties in the chain. However, the negotiating power of supply chain actors plays a role as well.