Donnelly is a city in rural Valley County, Idaho, United States.

The City of Donnelly, named after a prominent railroad man, was incorporated in 1914.

According to the United States Census Bureau, the city has a total area of 0.45 square miles (1.17 km2), all of it land.

[6] Donnelly is the gateway community for Tamarack Resort, which in 2014 emerged from foreclosure and restarted recreation activities.

35.0% of all households were made up of individuals, and 10% had someone living alone who was 65 years of age or older.

There were 33.3% of families and 31.4% of the population living below the poverty line, including 30.0% of under eighteens and 25.0% of those over 64.

In 2024, as a result of the Idaho State Legislature's House Bill 710, Donnelly Public Library became the first "adults-only" public library in the state in an attempt to comply with new restrictions on primarily LGBTQ- and sex education-themed materials.

[11] Donnelly is approximately 85 miles (137 km) north of Boise, accessed via State Highway 55, the Payette River Scenic Byway, a designated national scenic byway.