Located on the Mekong Delta, Long An is surrounded by Tay Ninh Province and Cambodia on the north, Ho Chi Minh City on east, Tien Giang Province on the south and Dong Thap Province on the west.
Long An is divided into smaller areas by a complex network of rives and canals. Silt from Vam Co Dong and Vam Co Tay rives has raised the level of the field of Long An. This silt makes a good condition for agriculture. The terrain is quite flat except some hills and mounds on the north. The western area belongs to the Plain of Reeds.