Kaiyuan is situated in northeastern Liaoning in the southeastern part of
Tieling City on the eastern bank of the middle reaches of the
Liao River. It borders
Dongfeng County and
Qingyuan Manchu Autonomous County to the east,
Tieling County to the south,
Faku and
Changtu counties to the west, and
Lishu County (
Jilin) to the north. Its administrative area reaches a maximal north–south extent of and east–west width of . In the east, the land begins to transition to the foothills of the
Changbai Mountains, while the west is marked by the
Songliao Plain. Kaiyuan has a
monsoon-influenced
humid continental climate (
Köppen Dwa), characterised by hot, humid summers and long, cold and windy, but dry winters. The four seasons here are distinctive. A majority of the annual rainfall of occurs in July and August alone. The monthly 24-hour average temperature ranges from in January to in July, and the annual mean is . Kaiyun was directly hit by
tornadoes in 2019 and 2023. ==Notable people==