A simple way to find any boundary is to launch www.osm.org and to navigate the map to that border. <br>Borderlines (ways) are violet dotted lines. <br>Once you see the borderline, expand the upper right icon on the map (layer stack), select Browse Map Data. <br>Better click Hide areas <br>With the hand, select the border and you see its tags on the left. <br>Click details and check that you've got what you want (that is a way, a borderline) <br>Click on the containing boundary relation you want at the bottom of the page <br>From there, depending if you're using subareas, you may be able to navigate up and down boundary levels. <br>Once found, click Edit Relation, JOSM recommended <br>Have fun

A simple way to find any boundary is to launch www.osm.org and to navigate the map to that border. <br>Borderlines (ways) are violet dotted lines. <br>Once you see the borderline, expand the upper right icon on the map (layer stack), select Browse Map Data. <br>Better click Hide areas <br>With the hand, select the border and you see its tags on the left. <br>Click details and check that you've got what you want (that is a way, a borderline) <br>Click on the boundary relation you want at the bottom of the page <br>From there, depending if you're using subareas, you may be able to navigate up and down boundary levels. <br>Once found, click Edit Relation, JOSM recommended <br>Have fun