Ethnic conflicts over land often coincide with statebuilding efforts. How do such conflicts shape state capacity? When migrants face threats to their property rights from indigenous groups, they are more likely to cooperate with state enumeration in return for property rights protection, especially if such threats to migrant property rights outweigh potential threats from the state, such as expropriation and taxation. This proposition is tested with demographic data from the 1940 Manchukuo Census disaggregated across ethnic groups and an illustrative village-level comparative case study. I find evidence consistent with theory in the case of Han Chinese settlement into Mongol Lands.