The crossword solution for the term COUNTY IN IDAHO is ADA. ADA is a county located in the state of Idaho. It is the fourth largest county in the state and is home to over 400, 000 people. The county seat is Boise, the state capital. ADA County is known for its agricultural production, including potatoes, wheat, and barley. It is also home to several universities and colleges, making it an educational hub in the region.