YnAMP add a selection list for City States in the advanced setup screen, with all the base game CS. You can add your own City States in that list by adding a few lines in a XML file loaded in <FrontEndActions> in the .modinfo Code: <FrontEndActions> <UpdateDatabase id="YOUR_SETTING"> <File>Configuration/Config.xml</File> </UpdateDatabase> </FrontEndActions> Config.xml Code: <Parameters> <Replace ParameterId="LEADER_MINOR_CIV_YOURMINORCIV" Name="LOC_CIVILIZATION_YOURMINORCIV_NAME" Description="LOC_CIVILIZATION_YOURMINORCIV_DESCRIPTION" Domain="bool" DefaultValue="0" ConfigurationGroup="Map" ConfigurationId="LEADER_MINOR_CIV_YOURMINORCIV" GroupId="MapOptions" SortIndex="90"/> </Parameters> <ParameterDependencies> <Replace ParameterId="LEADER_MINOR_CIV_YOURMINORCIV" ConfigurationGroup="Map" ConfigurationId="SelectCityStates" Operator="Equals" ConfigurationValue="1"/> </ParameterDependencies> The <ParameterDependencies> section tells the game to show your City State line(s) on the setup screen only when YnAMP "Manual Selection of City States" option is checked. The <Parameters> section contains the data for the line(s) that can be checked to select your minor civilization: ParameterId: an identifier, it must be the same in <ParameterDependencies> and <Parameters>. It doesn't need to be in the form of "LEADER_MINOR_CIV_XXX", but it must be unique and not used in another mod. Name, Description: the text shown on the setup screen line and its mouse over description, that have to be defined in a file loaded using <UpdateText> in the <FrontEndActions> of the .modinfo DefaultValue : 0 means the CS line is unchecked by default ConfigurationGroup : must be "Map" ConfigurationId : must be the exact <LeaderType> of your City State. That type name must contain (at the beginning, middle, or end, but exactly) the "LEADER_MINOR_CIV" string to be correctly identified as a City State by YnAMP. GroupId: must be "MapOptions" SortIndex: the position in the game/map section of the setup screen, must be a value between 83 and (I think) 200. "82" is the position of the YnAMP option to show the list, "83" is the position of all vanilla CS, "84" is the Viking DLC CS, "85" is the R&F CS and "86" is the Gathering Storm CS. So I'd suggest to skip a few (for a potential third XP or more DLC) and use values >90 and <200 for custom CS.