Emmett was originally called Martinsville, named after Nathaniel Martin who, along with Jonathan Smith, built the ferry crossing.

A few years later the "ville" was dropped and the post office and town became simply Emmett.

A series of irrigation projects made it possible for more rapid expansion of the town as the major service center for a farming and fruit-growing valley.

In the early 1900s fruit packers adopted the label of "Gem of Plenty" because of the fertility of the valley.

[8] While campaigning for a return to Congress in 1934, Robert M. McCracken died in an automobile accident near Emmett.

[10] The Black Canyon diversion dam on the Payette River, built in the early 1920s, is east of the city.

[11] Rising some 5,906 feet (1,800 m) above sea level, Squaw Butte, named by [Confederate Settlers new to the area]; Native Americans who used this area as their winter resort, stands at the north end of the valley.

Permanent settlement began in the early 1860s, after gold discoveries in the Boise Basin brought people over the established stage and pack train routes.

[12] It is located south of the Payette River, at an elevation of 2,362 feet (720 m) above sea level.

Emmett experiences a semi-arid climate (Köppen BSk) with cold, moist winters and hot, dry summers.

As of the 2020 United States census, there were 7,647 people, 2,773 households, and 1,790 families residing in the city.

[20] Residents of Gem County are in the area (but not the taxation zone) for College of Western Idaho.