Ilsanseo District (Korean: 일산서구; RR: Ilsanseo-gu; lit. West Ilsan District) is a district in Goyang, Gyeonggi-do, South Korea. Ilsan-gu was divided into Ilsandong District and Ilsanseo District on May 16, 2005.

It is a district located in the western part of Goyang-si, Gyeonggi-do. It has an area of ​​42.15㎢ and is divided into Ilsandong-gu to the east and Ilsanseo-gu to the west, centered on Gobong-ro, which connects Jungsan and Hosu Park. It borders Paju-si to the north and Gimpo-si to the west across the Han River.

Ilsanseo District is divided into 9 dong (동, "neighborhoods"):

• Ilsan 1(il), 2(i) and 3(sam)-dong (일산1, 2, 3동)
• Tanhyeon-dong (탄현동)
• Juyeop 1(il) and 2(i)-dong (주엽1, 2동)
• Daehwa-dong (대화동)
• Songpo-dong (송포동) [contain Beopgot-dong (법곳동)]
• Songsan-dong (송산동) [divided into Gusan-dong and Gajwa-dong (구산동, 가좌동)]
• Deogi-dong (덕이동)

Ilsanseo District has 46 schools including: 22 elementary schools, 12 middle schools, 9 high schools, and 2 special schools.^[1]

Hugok (후곡) is notable for their hagwons (학원, "cram school"), and many hagwons are present in the region.

To improve the living environment of ordinary citizens, 1,800 private rental housing units are scheduled to be built in Deok-i-dong.

• Ilsanseo District office website (Western Ilsan district) (in Korean)
• 블루밍 킨텍스 더센트 Deok-i-dong, scheduled for 2029
• Ilsanseo-gu Office