In this paper, we tried to estimate the economic impacts of the Central Asia Regional Economic Cooperation (CAREC) Economic Corridor 4a, 4b, and 4c projects, which enhance the connectivity between Mongolia and its surrounding countries, using a computational general equilibrium model based on spatial economics. The estimation results show that the economic impacts for Corridor 4b, which connects China and Russia through Ulaanbaatar, the capital of Mongolia, are the highest compared with the other two corridors. Apart from Mongolia, Corridor 4b also economically impacts China, EU, and Russia; thus, cooperation among these four parties might be a suitable arrangement for development. The evaluation of large-scale economic development of corridors is not very easy without proper evaluation tools
