The maturity of a district heating system can be estimated from its complexity. In fact, a mature network has a meshed structure while a younger network is often in the form of small network islands or has a tree structure. When a district heating system is developing and its complexity is increasing the flow distribution in the network is no longer obvious. As a consequence, the network owner, often the local energy company, is in need of a simulation program to have the possibility of analysing it and enlarge their network understanding. In this paper, a simulation tool developed in MATLAB/Simulink is applied in order to analyse the flow distribution in the district heating network of the town of Kiruna (Sweden). The Kiruna network has been developing since the 60s and is today a mature network with the meshed structure. The method has specifically been developed to analyse the flow pattern in such kind of networks without altering their physical structure, and it is expected to be a valuable tool for the redesign of the network in the forthcoming relocation of some of the urban districts. The results about the current network configuration show that only a few pipes in the network are exceeding the recommended level of flow in terms of thermal power. The temperature and pressure drop from heat production site to the nodes serving the main consumer areas is within 1.6 bar and 10°C in the days of highest demand.