When Does The Boise Fair Open. Admission is free during the first couple hours, but you have to stay a little longer to get a hand stamp. Western idaho fair, a regional event attracting more than 267,000 patrons from oregon, washington, idaho, utah and northern california, is the largest event in idaho.

People flocked to the fair for the exhibition and social gathering, spending money in the. A second economic benefit for the fair was the increase in local businesses to boise.