Lostant is a village in LaSalle County, Illinois, United States.

[5] Horatio N. Boshell (1872–1933), Illinois state representative and physician, was born in Lostant.

[7] The village limits extend south to the Marshall County line.

Interstate 39 runs along the southwestern edge of the village, with access from Exit 41 (IL 18).

According to the 2021 census gazetteer files, Lostant has a total area of 1.13 square miles (2.93 km2), all land.