Simms is a census-designated place (CDP) in Cascade County, Montana, United States.

According to the United States Census Bureau, the CDP has a total area of 7.7 square miles (20 km2), of which 0.13% is water.

[4] The town of Simms, surrounded by buttes and benches, was built on a low spot in the Sun River valley.

In 1902 President Theodore Roosevelt signed the Reclamation Act, and in 1906 the Sun River Irrigation Project was begun.

The creek was named after a pair of brothers who were woodcutters along the Sun River in earlier days.

As of the census[6][failed verification] of 2000, there were 373 people, 148 households, and 103 families residing in the CDP.