tried to translate something through google
geez...
"In the media, it is not difficult to find cases where'Ilsan-dong-gu, Goyang-si' is marked as'Dong-gu, Ilsan-si. There are many people who know Goyang itself as'Ilsan' or call it'Ilsan City'. However, in Ilsan, Ilsandong-gu, Goyang-si or Ilsanseo-gu, Goyang-si are the correct names of administrative districts, and there are'Ilsandong-gu','Ilsanseo-gu' and'Deokyang-gu' in Goyang-si."
but hold on it's not all
this part is also interesting
"Even longer ago, when Goyang-si was in Goyang-gun, Ilsan was in Ilsan-myeon, Goyang-gun. Later, it became Ilsan-eup, but it was still part of Goyang-gun. However, as the population rapidly increased, Goyang-gun became Goyang-si, and as a ward was created, Ilsan-eup was naturally named Ilsan-gu."